text:
South Carolina in the American Civil War
From Wikipedia, the free encyclopedia
Jump to: navigation, search
State of South Carolina
Nickname(s): "Palmetto Republic"

Flag
Coat of arms

Map of the United States with South Carolina highlighted.
Capital
Columbia
Largest City
Charleston
Admission to confederacy
February 4, 1861 (1st)
Population
703,708 total
• 301,302 free
• 402,406 slave
Forces supplied
23% of white population total
• 12,992 killed
Major garrisons/armories
Fort Sumter, Charleston Harbor
Governor
Francis Pickens (1860–1862)
Milledge Bonham
Andrew Magrath
Senators
Robert Woodward Barnwell
James Lawrence Orr
Representatives
List
Restored to the Union
July 9, 1868
Part of a series on the
History of South Carolina
Timeline
Colonial period 1651–1774
American Revolution 1775–1788
Antebellum period 1812–1860
Civil War era 1861–1865
Reconstruction 1865–1877
State of South Carolina
South Carolina portal
v
t
e
Confederate States
in the
American Civil War
South Carolina
Mississippi
Florida
Alabama
Georgia
Louisiana
Texas
Virginia
Arkansas
North Carolina
Tennessee
Border states
Delaware
Maryland
West Virginia
Kentucky
Missouri
Dual governments
Missouri
Kentucky
West Virginia
Virginia
Tennessee
Territories
Arizona Territory
Indian Territory
v
t
e
South Carolina was the first state to secede from the Union (Dec. 1860), and was one of the founder members of the Confederacy (Feb. 1861). The bombardment of the beleaguered U.S. garrison at Fort Sumter in Charleston Harbor on April 12, 1861 is normally reckoned as the first military engagement of the war.
South Carolina was a source of troops for the Confederate army, and as the war progressed, also for the Union, as thousands of ex-slaves flocked to join the Union. The state also provided uniforms, textiles, food, and war material, as well as trained soldiers and leaders from The Citadel and other military schools. In contrast to most other Confederate states, South Carolina had a well-developed rail network linking all of its major cities without a break of gauge. Relatively free from Union occupation until the very end of the war, South Carolina hosted a number of prisoner of war camps. South Carolina also was the only Confederate state not to harbor pockets of anti-secessionist fervor strong enough to send large amounts of white men to fight for the Union, as every other state in the Confederacy did.
Among the leading generals from the Palmetto State were Wade Hampton III, one of the Confederacy's foremost cavalry commanders, Maxcy Gregg, killed in action at Fredericksburg, Joseph B. Kershaw, whose South Carolina infantry brigade saw some of the hardest fighting of the Army of Northern Virginia and James Longstreet, the senior Lieutenant General in the army, and Stephen D. Lee, the youngest Lieutenant General.
Contents
[hide]
1 Background
2 Secession
3 American Civil War
3.1 Fort Sumter
3.2 Fort Wagner
3.3 The war ends
4 Battles in South Carolina
5 See also
6 Notes
7 References
8 Further reading
9 External links
Background[edit]
The white population of the state had strongly supported the institution of slavery since the 18th century. Political leaders such as Democrats John Calhoun and Preston Brooks had inflamed regional and national passions in support of the institution, and many pro-slavery voices had cried for secession. On the outbreak of war, South Carolina had the highest percentage of slaves of any U.S. state at 57% of its population enslaved; 46% of its white families owned at least one slave.
For decades, South Carolinian political leaders had promoted regional passions with threats of nullification and secession in the name of southern states' rights and protection of the interests of the slave power.
Alfred P. Aldrich, a South Carolinian politician from Barnwell, stated that declaring secession would be necessary if a Republican candidate were to win the 1860 U.S. presidential election, stating that it was the only way for the state to preserve slavery and diminish the influence of the anti-slavery Republican Party, which, were its goals of abolition realized, would result in the "destruction of the South":
If the Republican party with its platform of principles, the main feature of which is the abolition of slavery and, therefore, the destruction of the South, carries the country at the next Presidential election, shall we remain in the Union, or form a separate Confederacy? This is the great, grave issue. It is not who shall be President, it is not which party shall rule – it is a question of political and social existence.
—  Alfred P. Aldrich, [1]
In a January 1860 speech, South Carolinian congressman Laurence Massillon Keitt, summed up this view in an oratory condemning the Republican Party for its anti-slavery views, claiming that slavery was not morally wrong, but rather, justified:
The anti-slavery party contends that slavery is wrong in itself, and the Government is a consolidated national democracy. We of the South contend that slavery is right...
—  Laurence Massillon Keitt, Speech to the House, (January 1860).[2]
Later that year, in December, Keitt would state that South Carolina's declaring of secession was the direct result of slavery:
Our people have come to this on the question of slavery.
—  Laurence Massillon Keitt, South Carolina secession debates, (December 1860).[3]
Secession[edit]
On November 9, 1860 the South Carolina General Assembly passed a "Resolution to Call the Election of Abraham Lincoln as U.S. President a Hostile Act" and stated its intention to declare secession from the United States.[4]
In December 1860, amid the secession crisis, former South Carolinian congressman John McQueen wrote to a group of civic leaders in Richmond, Virginia, regarding the reasons as to why South Carolina was contemplating secession from the Union. In the letter, McQueen claimed that U.S. president-elect Abraham Lincoln supported equality and civil rights for African Americans as well as the abolition of slavery, and thus South Carolina, being opposed to such measures, was compelled to secede:
I have never doubted what Virginia would do when the alternatives present themselves to her intelligent and gallant people, to choose between an association with her sisters and the dominion of a people, who have chosen their leader upon the single idea that the African is equal to the Anglo-Saxon, and with the purpose of placing our slaves on equality with ourselves and our friends of every condition! and if we of South Carolina have aided in your deliverance from tyranny and degradation, as you suppose, it will only the more assure us that we have performed our duty to ourselves and our sisters in taking the first decided step to preserve an inheritance left us by an ancestry whose spirit would forbid its being tarnished by assassins. We, of South Carolina, hope soon to great you in a Southern Confederacy, where white men shall rule our destinies, and from which we may transmit to our posterity the rights, privileges and honor left us by our ancestors.
—  John McQueen, Correspondence to T.T. Cropper and J.R. Crenshaw, (December 24, 1860)[5][6]
South Carolinian religious leader James Henley Thornwell also espoused a similar view to McQueen's, stating that slavery was justified under the Christian religion, and thus, those who viewed slavery as being immoral were opposed to Christianity:
The parties in the conflict are not merely abolitionists and slaveholders. They are atheists, socialists, communists, red republicans, Jacobins on the one side, and friends of order and regulated freedom on the other. In one word, the world is the battleground – Christianity and Atheism the combatants; and the progress of humanity at stake.
—  James Henley Thornwell, [6]
Other religious institutions in South Carolina also expressed support for slavery. The Southern Presbyterian of S.C. declared that:
Anti-slavery is essentially infidel. It wars upon the Bible, on the Church of Christ, on the truth of God, on the souls of men.
—  Southern Presbyterian of S.C., [6]
On November 10, 1860 the S.C. General Assembly called for a "Convention of the People of South Carolina" to consider secession. Delegates were to be elected on December 6.[7] The secession convention convened in Columbia on December 17 and voted unanimously, 169-0, to declare secession from the United States. The convention then adjourned to Charleston to draft an ordinance of secession. When the ordinance was adopted on December 20, 1860, South Carolina became the first slave state in the south to declare that it had seceded from the United States.[8][9] James Buchanan, the United States president, declared the ordinance illegal but did not act to stop it.
A committee of the convention also drafted a Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina which was adopted on December 24.[10] The secession declaration stated the primary reasoning behind South Carolina's declaring of secession from the Union, which was described as:
...increasing hostility on the part of the non-slaveholding States to the Institution of Slavery ...
—  Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina, (December 24, 1860).[10]
The declaration also claims that secession was declared as a result of the refusal of free states to enforce the Fugitive Slave Acts. Although the declaration does argue that secession is justified on the grounds of U.S. "encroachments upon the reserved rights of the States," the grievances that the declaration goes on to list are mainly concerned with the property of rights of slave holders. Broadly speaking, the declaration argues that the U.S. Constitution was framed to establish each State "as an equal" in the Union, with "separate control over its own institutions", such as "the right of property in slaves."
We affirm that these ends for which this Government was instituted have been defeated, and the Government itself has been made destructive of them by the action of the non-slaveholding States. Those States have assumed the right of deciding upon the propriety of our domestic institutions; and have denied the rights of property established in fifteen of the States and recognized by the Constitution; they have denounced as sinful the institution of Slavery; they have permitted the open establishment among them of societies, whose avowed object is to disturb the peace and to eloign the property of the citizens of other States. They have encouraged and assisted thousands of our slaves to leave their homes; and those who remain, have been incited by emissaries, books and pictures to servile insurrection.
—  Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina, [11]
A repeated concern is runaway slaves. The declaration argues that parts of the U.S. Constitution were specifically written to ensure the return of slaves who had escaped to other states, and quotes the 4th Article: "No person held to service or labor in one State, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor, but shall be delivered up, on claim of the party to whom such service or labor may be due." The declaration goes on to state that this stipulation of the Constitution was so important to the original signers, "that without it that compact [the Constitution] would not have been made." Laws from the "General Government" upheld this stipulation "for many years," the declaration says, but "an increasing hostility on the part of the non-slaveholding States to the Institution of Slavery has led to a disregard of their obligations." Because the constitutional agreement had been "deliberately broken and disregarded by the non-slaveholding States," the consequence was that "South Carolina is released from her obligation" to be part of the Union.
A further concern was Lincoln's recent election to the presidency, whom they claimed desired to see slavery on "the course of ultimate extinction":
A geographical line has been drawn across the Union, and all the States north of that line have united in the election of a man to the high office of President of the United States whose opinions and purposes are hostile to slavery. He is to be entrusted with the administration of the Common Government, because he has declared that that "Government cannot endure permanently half slave, half free," and that the public mind must rest in the belief that Slavery is in the course of ultimate extinction.[11]
The South Carolinian secession declaration of December 1860 also channeled some elements from the U.S. Declaration of Independence from July 1776. However, the South Carolinian version omitted the phrases that "all men are created equal", "that they are endowed by their Creator with certain unalienable Rights", and mentions of the "consent of the governed". Professor and historian Harry V. Jaffa noted these omissions as significant in his 2000 book, A New Birth of Freedom: Abraham Lincoln and the Coming of the Civil War:
South Carolina cites, loosely, but with substantial accuracy, some of the language of the original Declaration. That Declaration does say that it is the right of the people to abolish any form of government that becomes destructive of the ends for which it was established. But South Carolina does not repeat the preceding language in the earlier document: 'We hold these truths to be self-evident, that all men are created equal'...
—  Harry Jaffa, A New Birth of Freedom: Abraham Lincoln and the Coming of the Civil War, (2000)[12]
Jaffa states that South Carolina omitted references to human equality and consent of the governed, as due to their racist and pro-slavery views, secessionist South Carolinians did not believe in those ideals:
[G]overnments are legitimate only insofar as their "just powers" are derived "from the consent of the governed." All of the foregoing is omitted from South Carolina's declaration, for obvious reasons. In no sense could it have been said that the slaves in South Carolina were governed by powers derived from their consent. Nor could it be said that South Carolina was separating itself from the government of the Union because that government had become destructive of the ends for which it was established. South Carolina in 1860 had an entirely different idea of what the ends of government ought to be from that of 1776 or 1787. That difference can be summed up in the difference between holding slavery to be an evil, if possibly a necessary evil, and holding it to be a positive good.
—  Harry Jaffa, A New Birth of Freedom: Abraham Lincoln and the Coming of the Civil War, (2000), emphasis added.[12]
On December 25, the day following South Carolina's declaration of secession, a South Carolinian convention delivered an "Address to the Slaveholding States":
We prefer, however, our system of industry, by which labor and capital are identified in interest, and capital, therefore, protects labor–by which our population doubles every twenty years–by which starvation is unknown, and abundance crowns the land–by which order is preserved by unpaid police, and the most fertile regions of the world, where the white man cannot labor, are brought into usefulness by the labor of the African, and the whole world is blessed by our own productions. ... We ask you to join us, in forming a Confederacy of Slaveholding States.
—  Convention of South Carolina, Address of the people of South Carolina to the people of the Slaveholding States, (December 25, 1860)[13]
"Slavery, not states' rights, birthed the Civil War,"[14] argues sociologist James W. Loewen. Writing of South Carolina's Declaration of Secession, Loewen writes that
South Carolina was further upset that New York no longer allowed "slavery transit." In the past, if Charleston gentry wanted to spend August in the Hamptons, they could bring their cook along. No longer — and South Carolina's delegates were outraged. In addition, they objected that New England states let black men vote and tolerated abolitionist societies. According to South Carolina, states should not have the right to let their citizens assemble and speak freely when what they said threatened slavery. Other seceding states echoed South Carolina. "Our position is thoroughly identified with the institution of slavery — the greatest material interest of the world," proclaimed Mississippi in its own secession declaration, passed Jan. 9, 1861. "Its labor supplies the product which constitutes by far the largest and most important portions of the commerce of the earth. . . . A blow at slavery is a blow at commerce and civilization."
—  James W. Loewen, The Washington Post, (2011)[14]
The state adopted the palmetto flag as its banner, a slightly modified version of which is used as its current state flag.[15] South Carolina after secession was frequently called the "Palmetto Republic".[16]
After South Carolina declared its secession, former congressman James L. Petigru famously remarked, "South Carolina is too small for a republic and too large for an insane asylum."[17] Soon afterwards, South Carolina began preparing for a presumed U.S. military response while working to convince other southern states to secede as well and join in a confederacy of southern states.
On February 4, 1861, in Montgomery, Alabama, a convention consisting of delegates from South Carolina, Florida, Alabama, Mississippi, Georgia, and Louisiana met to form a new constitution and government modeled on that of the United States.[18] On February 8, 1861, South Carolina officially joined the Confederacy. According to one South Carolinian newspaper editor:
The South is now in the formation of a Slave Republic...
—  L.W. Spratt, The Philosophy of Secession: A Southern View, (February 13, 1861).[19]
South Carolina's declaring of secession was supported by the state's religious figures, who claimed that it was consistent with the tenets of their religion:
The triumphs of Christianity rest this very hour upon slavery; and slavery depends on the triumphs of the South... This war is the servant of slavery.
—  John T. Wightman, The Glory of God, the Defence of the South, (1861).[20]
American Civil War[edit]
1862 U.S. Coast Survey map of the Coast of South Carolina from Charleston to Hilton Head
Fort Sumter[edit]
Fort Sumter, 1861, flying the Confederate flag after the fort's capture from the U.S. by the Confederacy.
Six days after secession, on the day after Christmas, Major Robert Anderson, commander of the U.S. troops in Charleston, withdrew his men to the island fortress of Fort Sumter in Charleston Harbor. South Carolina militia swarmed over the abandoned mainland batteries and trained their guns on the island. Sumter was the key position for preventing a naval attack upon Charleston, so secessionists were determined not to allow U.S. forces to remain there indefinitely. More importantly, South Carolina's claim of independence would look empty if U.S. forces controlled its largest harbor. On January 9, 1861, the U.S. ship Star of the West approached to resupply the fort. Cadets from The Citadel, The Military College of South Carolina fired upon the Star of the West, striking the ship three times and causing it to retreat back to New York.
Mississippi declared its secession several weeks after South Carolina, and five other states of the lower South soon followed. Both the outgoing Buchanan administration and President-elect Lincoln denied that any state had a right to secede. On February 4, a congress of the seven seceding states met in Montgomery, Alabama, and approved a new constitution for the Confederate States of America. South Carolina entered the Confederacy on February 8, 1861, fewer than six weeks after declaring itself the independent State of South Carolina.
Upper Southern slave states such as Virginia and North Carolina, which had initially voted against secession, called a peace conference, to little effect. Meanwhile, Virginian orator Roger Pryor barreled into Charleston and proclaimed that the only way to get his state to join the Confederacy was for South Carolina to instigate war with the United States. The obvious place to start was right in the midst of Charleston Harbor.
On April 10, the Mercury reprinted stories from New York papers that told of a naval expedition that had been sent southward toward Charleston. Lincoln advised the governor of South Carolina that the ships were sent to resupply the fort, not to reinforce it. The Carolinians could no longer wait if they hoped to take the fort before the U.S. Navy arrived. About 6,000 men were stationed around the rim of the harbor, ready to take on the 60 men in Fort Sumter. At 4:30 a.m. on April 12, after two days of intense negotiations, and with Union ships approaching the harbor, the firing began. Students from The Citadel were among those firing the first shots of the war, though Edmund Ruffin is usually credited with firing the first shot. Thirty-four hours later, Anderson's men raised the white flag and were allowed to leave the fort with colors flying and drums beating, saluting the U.S. flag with a 50-gun salute before taking it down. During this salute, one of the guns exploded, killing a young soldier—the only casualty of the bombardment and the first casualty of the war.
In December 1861, South Carolina received $100,000 from Georgia after a disastrous fire in Charleston.
Fort Wagner[edit]
Fort Wagner was the scene of two battles. The First Battle of Fort Wagner, occurred on July 11, 1863. Only 12 Confederate soldiers were killed, as opposed to the Union's 339 losses.[21]
54th Massachusetts Regiment charging towards Fort Wagner
The Second Battle of Fort Wagner, a week later, is better known. This was the Union attack on July 18, 1863, led by the 54th Massachusetts Volunteer Infantry, one of the first major American military units made up of black soldiers. Colonel Robert Gould Shaw led the 54th Massachusetts on foot while they charged, and was killed in the assault.[21]
Although a tactical defeat, the publicity of the battle of Fort Wagner led to further action for black troops in the Civil War, and it spurred additional recruitment that gave the Union Army a further numerical advantage in troops over the South.[21]
The Union besieged the fort after the unsuccessful assault. By August 25, Union entrenchments were close enough to attempt an assault on the Advanced Rifle Pits, 240 yards in front of the Battery, but this attempt was defeated. A second attempt, by the 24th Mass. Inf., on August 26 was successful. After enduring almost 60 days of heavy shelling, the Confederates abandoned it on the night of September 6–7, 1863. withdrawing all operable cannons and the garrison.[21][22]
The war ends[edit]
The Confederacy was at a disadvantage in number, weaponry, and supplies. Union ships sailed south and blocked off one port after another. As early as November, Union troops occupied the Sea Islands in the Beaufort area, establishing an important base for the men and ships who would obstruct the ports at Charleston and Savannah. When the plantation owners, many of which had already gone off with the Confederate army elsewhere, fled the area, the Sea Island slaves became the first "freedmen" of the war, and the Sea Islands became the laboratory for Union plans to educate the African Americans for their eventual role as full American citizens Despite South Carolina's important role in the start of the war, and a long unsuccessful attempt to take Charleston from 1863 onward, few military engagements occurred within the state's borders until 1865, when Sherman's Army, having already completed its March to the Sea in Savannah, marched to Columbia and leveled most of the town, as well as a number of towns along the way and afterward. South Carolina lost 12,922 men to the war, 23% of its male white population of fighting age, and the highest percentage of any state in the nation. Sherman's 1865 march through the Carolinas resulted in the burning of Columbia and numerous other towns. The destruction his troops wrought upon South Carolina was even worse than in Georgia, because many of his men bore a particular grudge against the state and its citizens, who they blamed for starting the war. One of Sherman's men declared, "Here is where treason began and, by God, here is where it shall end!"[23] Poverty would mark the state for generations to come.
In January 1865, the Charleston Courier newspaper condemned suggestions that the Confederacy abandon slavery were it to help in gaining independence, stating that such suggestions were "folly":
To talk of maintaining our independence while we abolish slavery is simply to talk folly.
—  Courier, (January 24, 1865)[24]
On February 21, 1865, with the Confederate forces finally evacuated from Charleston, the black 54th Massachusetts Regiment marched through the city. At a ceremony at which the U.S. flag was once again raised over Fort Sumter, former fort commander Robert Anderson was joined on the platform by two men: African American Union hero Robert Smalls and the son of Denmark Vesey.
Battles in South Carolina[edit]
Battle of Fort Sumter
Battle of Port Royal
Battle of Secessionville
Battle of Simmon's Bluff
First Battle of Charleston Harbor
Second Battle of Charleston Harbor
Second Battle of Fort Sumter
First Battle of Fort Wagner
Battle of Grimball's Landing
Second Battle of Fort Wagner (Morris Island)
Battle of Honey Hill
Battle of Tulifinny
Battle of Rivers' Bridge
Battle of Anderson County
Battle of Brattonsville
Battle of Broxton's Bridge
Battle of Cheraw
Battle of Gamble's Hotel (The Columns)
Battle of Aiken
See also[edit]
Charleston, South Carolina in the American Civil War
Confederate States of America - animated map of state secession and confederacy
List of South Carolina Confederate Civil War units
List of South Carolina Union Civil War units
Military history of African Americans in the American Civil War
Origins of the American Civil War
Slavery during the American Civil War
Port Royal Experiment
Edisto Island during the Civil War
Notes[edit]
Jump up ^ Channing, Steven. Crisis of Fear. pp. 141–142. Retrieved September 6, 2015.
Jump up ^ Keitt, Lawrence M. (January 25, 1860). Congressman from South Carolina, in a speech to the House. Taken from a photocopy of the Congressional Globe, supplied by Steve Miller. The anti-slavery party contends that slavery is wrong in itself, and the Government is a consolidated national democracy. We of the South contend that slavery is right, and that this is a confederate Republic of sovereign States.
Jump up ^ "The Charleston Courier". Charleston, South Carolina. December 22, 1860. Retrieved September 6, 2015.
Jump up ^ "Resolution to Call the Election of Abraham Lincoln as U.S. President a Hostile Act and to Communicate to Other Southern States South Carolina's Desire to Secede from the Union." 9 November 1860. Resolutions of the General Assembly, 1779–1879. S165018. South Carolina Department of Archives and History, Columbia, South Carolina.
Jump up ^ McQueen, John (December 24, 1860). "Correspondence to T. T. Cropper and J. R. Crenshaw". Washington, D.C. Archived from the original on March 25, 2015. Retrieved March 25, 2015. CS1 maint: Unfit url (link)
^ Jump up to: a b c Rhea, Gordon (January 25, 2011). "Why Non-Slaveholding Southerners Fought". Civil War Trust. Civil War Trust. Archived from the original on March 21, 2011. Retrieved March 21, 2011. CS1 maint: Unfit url (link)
Jump up ^ Cauthen, Charles Edward; Power, J. Tracy. South Carolina goes to war, 1860–1865. Columbia, SC: University of South Carolina Press, 2005. Originally published: Chapel Hill, NC: University of North Carolina Press, 1950. ISBN 978-1-57003-560-9. p. 60.
Jump up ^ "Results from the 1860 Census". 1860 United States Census. 1860. Archived from the original on June 4, 2004. Retrieved June 4, 2004. CS1 maint: Unfit url (link)
Jump up ^ Hall, Andy (December 22, 2013). "Not Surprising, Part Deux". Dead Confederates: A Civil War Era Blog. The states with the largest proportions of slaves and slave-holders seceded earliest.
^ Jump up to: a b "'Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina from the Federal Union,' 24 December 1860". Teaching American History in South Carolina Project. 2009. Retrieved November 18, 2012.
^ Jump up to: a b https://en.wikisource.org/wiki/Declaration_of_the_Immediate_Causes_Which_Induce_and_Justify_the_Secession_of_South_Carolina_from_the_Federal_Union
^ Jump up to: a b Jaffa, Harry V. (2000). A New Birth of Freedom: Abraham Lincoln and the Coming of the Civil War. Rowman & Littlefield Publishers. p. 231. ISBN 9780847699520.
Jump up ^ State of South Carolina (December 25, 1860). "Address of the people of South Carolina to the people of the Slaveholding States of the United States". Retrieved March 27, 2015.
^ Jump up to: a b Loewen, James (2011). "Five Myths About Why the South Seceded". Washington Post.
Jump up ^ Edgar, Walter. South Carolina: A History, Columbia, SC: University of South Carolina Press:1998. ISBN 978-1-57003-255-4. p. 619
Jump up ^ Cauthen, Charles Edward; Power, J. Tracy. South Carolina goes to war, 1860–1865. Columbia, SC: University of South Carolina Press, 2005. Originally published: Chapel Hill, NC: University of North Carolina Press, 1950. ISBN 978-1-57003-560-9. p. 79.
Jump up ^ Burger, Ken (February 13, 2010). "Too large to be an asylum". The Post and Courier. Charleston, South Carolina: Evening Post Publishing Co. Retrieved April 22, 2010. Paragraph 4
Jump up ^ Lee, Jr., Charles Robert. The Confederate Constitutions. Chapel Hill, NC: The University of North Carolina Press, 1963, 60.
Jump up ^ Spratt, L.W. (February 13, 1861). "THE PHILOSOPHY OF SECESSION: A SOUTHERN VIEW". South Carolina. Retrieved September 13, 2015. Presented in a Letter addressed to the Hon. Mr. Perkins of Louisiana, in criticism on the Provisional Constitution adopted by the Southern Congress at Montgomery, Alabama, BY THE HON. L. W. SPRATT, Editor of the Charleston Mercury, 13th February, 1861.
Jump up ^ Wightman, John T. (1861). "The Glory of God, the Defence of the South". Yorkville, South Carolina. Retrieved September 8, 2015.
^ Jump up to: a b c d The 54th and Fort Wagner
Jump up ^ Wittenburg, Eric J., The Battle of Tom's Brook North & South - The Official Magazine of the Civil War Society, Volume 10, Number 1, Page 30.
Jump up ^ McPherson, James M. This Mighty Scourge: Perspectives on the Civil War. Oxford University Press, 2009
Jump up ^ "Courier". Charleston. January 24, 1865. Retrieved September 8, 2015.
References[edit]
Burger, Ken (February 13, 2010). "Too large to be an asylum". The Post and Courier. Charleston, South Carolina: Evening Post Publishing Co. Retrieved April 22, 2010. .
Cauthen, Charles Edward; Power, J. Tracy. South Carolina goes to war, 1860–1865. Columbia, SC: University of South Carolina Press, 2005. Originally published: Chapel Hill, NC: University of North Carolina Press, 1950. ISBN 978-1-57003-560-9.
Edgar, Walter. South Carolina: A History, Columbia, SC: University of South Carolina Press:1998. ISBN 978-1-57003-255-4.
Rogers Jr. George C. and C. James Taylor. A South Carolina Chronology, 1497-1992 2nd Ed. (1994)
Wallace, David Duncan. South Carolina: A Short History, 1520-1948 (1951) standard scholarly history
WPA. South Carolina: A Guide to the Palmetto State (1941)
Wright, Louis B. South Carolina: A Bicentennial History' (1976)
Further reading[edit]
Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina from the Federal Union
External links[edit]
Wikiquote has quotations related to: American Civil War
Wikiquote has quotations related to: Confederate States of America
National Park Service map of Civil War sites in South Carolina
[show]
v
t
e
South Carolina in the American Civil War
1861
Battle of Fort Sumter
Battle of Port Royal
1862
First Battle of Pocotaligo
Battle of Secessionville
Battle of Simmon's Bluff
Second Battle of Pocotaligo
1863
First Battle of Charleston Harbor
First Battle of Fort Wagner
Battle of Grimball's Landing
Second Battle of Fort Wagner
Second Battle of Charleston Harbor
Second Battle of Fort Sumter
Atttack on USS New Ironsides
1864
Sinking of USS Housatonic by Hunley
Battle of Honey Hill
Battle of Tulifinny
1865
Battle of Rivers' Bridge
Grimball's Causeway/Surrender of Charleston
Capture of Columbia
Units
Confederate
Units
Places
Charleston
Columbia
Category
[hide]
v
t
e
American Civil War
[show]
Origins
Origins
Issues
Timeline leading to the War
Antebellum era
Bleeding Kansas
Border states
Compromise of 1850
Dred Scott v. Sandford
Lincoln-Douglas debates
Missouri Compromise
Popular sovereignty
Secession
States' rights
President Lincoln's 75,000 volunteers
Slavery
African Americans
Cornerstone Speech
Emancipation Proclamation
Fugitive slave laws
Plantations in the American South
Slave Power
Slavery in the United States
Treatment of slaves in the United States
Uncle Tom's Cabin
Abolitionism
Susan B. Anthony
John Brown
Frederick Douglass
William Lloyd Garrison
Elijah Parish Lovejoy
J. Sella Martin
Lysander Spooner
George Luther Stearns
Thaddeus Stevens
Charles Sumner
Harriet Tubman
Underground Railroad
[show]
Combatants
Theaters
Campaigns
Battles
States
Combatants
Union (USA)
Army
Navy
Marine Corps
Revenue Cutter Service
Confederacy (CSA)
Army
Navy
Marine Corps
Theaters
Eastern
Western
Lower Seaboard
Trans-Mississippi
Pacific Coast
Union naval blockade
Major Campaigns
Anaconda Plan
Blockade runners
New Mexico
Jackson's Valley
Peninsula
Northern Virginia
Maryland
Stones River
Vicksburg
Tullahoma
Gettysburg
Morgan's Raid
Bristoe
Knoxville
Red River
Overland
Atlanta
Valley 1864
Bermuda Hundred
Richmond-Petersburg
Franklin–Nashville
Price's Raid
Sherman's March
Carolinas
Appomattox
Major battles
Fort Sumter
1st Bull Run
Wilson's Creek
Fort Donelson
Pea Ridge
Hampton Roads
Shiloh
New Orleans
Corinth
Seven Pines
Seven Days
2nd Bull Run
Antietam
Perryville
Fredericksburg
Stones River
Chancellorsville
Gettysburg
Vicksburg
Chickamauga
Chattanooga
Wilderness
Spotsylvania
Cold Harbor
Atlanta
Mobile Bay
Franklin
Nashville
Five Forks
Involvement (by
state or territory)
AL
AK
AR
AZ
CA
CO
CT
DC
DE
FL
GA
HI
ID
IL
IN
IA
KS
KY
LA
ME
MD
MA
MI
MN
MS
MO
MT
NE
NV
NH
NJ
NM
NY
NC
ND
OH
OK
OR
PA
RI
SC
SD
TN
TX
UT
VT
VA
WA
WV
WI
WY
[show]
Leaders
Confederate
Military
R. H. Anderson
Beauregard
Bragg
Buchanan
Cooper
Early
Ewell
Forrest
Gorgas
Hill
Hood
Jackson
A. S. Johnston
J. E. Johnston
Lee
Longstreet
Morgan
Mosby
Price
Semmes
E. K. Smith
Stuart
Taylor
Wheeler
Civilian
Benjamin
Bocock
Breckinridge
Davis
Hunter
Mallory
Memminger
Seddon
Stephens
Union
Military
Anderson
Buell
Burnside
Butler
Du Pont
Farragut
Foote
Frémont
Grant
Halleck
Hooker
Hunt
McClellan
McDowell
Meade
Meigs
Ord
Pope
D. D. Porter
Rosecrans
Scott
Sheridan
Sherman
Thomas
Civilian
Adams
Chase
Ericsson
Hamlin
Lincoln
Pinkerton
Seward
Stanton
Stevens
Wade
Welles
[show]
Aftermath
U.S. Constitution
Reconstruction amendments
13th Amendment
14th Amendment
15th Amendment
Reconstruction
Alabama Claims
Brooks–Baxter War
Carpetbaggers
Colfax Riot of 1873
Eufaula Riot of 1874
Freedmen's Bureau
Freedman's Savings Bank
Impeachment of Andrew Johnson
Kirk-Holden War
Knights of the White Camelia
Ku Klux Klan
Memphis Riot of 1866
Meridian Riot of 1871
New Orleans Riot of 1866
Pulaski (Tennessee) Riot of 1867
Reconstruction acts
Habeas Corpus Act 1867
Enforcement Act of 1870
Enforcement Act of February 1871
Enforcement Act of April 1871
Reconstruction treaties
Indian Council at Fort Smith
Red Shirts
Redeemers
Confederate refugees
Confederados
Scalawags
South Carolina riots of 1876
Southern Claims Commission
Homestead acts
Southern Homestead Act of 1866
Timber Culture Act of 1873
White League
post-Reconstruction
Commemoration
Centennial
Civil War Discovery Trail
Civil War Roundtables
Civil War Trails Program
Civil War Trust
Confederate History Month
Confederate monuments and memorials
Historical reenactment
Robert E. Lee Day
Disenfranchisement
Black Codes
Jim Crow
Lost Cause mythology
Modern display of the Confederate flag
Sons of Confederate Veterans
Sons of Union Veterans of the Civil War
Southern Historical Society
United Daughters of the Confederacy
Monuments and memorials
Union
List of Union Civil War monuments and memorials
List of memorials to the Grand Army of the Republic
Memorials to Abraham Lincoln
Confederate
List of Confederate monuments and memorials
Removal of Confederate monuments and memorials
List of memorials to Robert E. Lee
List of memorials to Jefferson Davis
Annapolis
Roger B. Taney Monument
Baltimore
Confederate Soldiers and Sailors Monument
Confederate Women's Monument
Roger B. Taney Monument
Robert E. Lee and Stonewall Jackson Monument
Durham, North Carolina
Robert E. Lee Monument
New Orleans
Battle of Liberty Place Monument
Jefferson Davis Monument
General Beauregard Equestrian Statue
Robert E. Lee Monument
Cemeteries
Confederate Memorial Day
Ladies' memorial associations
U.S. Memorial Day
U.S. national cemeteries
Veterans
1913 Gettysburg Reunion
Confederate Veteran
Grand Army of the Republic
Military Order of the Loyal Legion of the U.S.
Old soldiers' homes
Southern Cross of Honor
United Confederate Veterans
[show]
Related topics
Related topics
Military
Arms
Campaign Medal
Cavalry
Confederate Home Guard
Confederate railroads
Confederate Revolving Cannon
Field artillery
Medal of Honor recipients
Medicine
Leadership
Naval battles
Official Records
Partisan rangers
POW camps
Rations
Signal Corps
Turning point
Union corps badges
U.S. Balloon Corps
U.S. Home Guard
U.S. Military Railroad
Political
Committee on the Conduct of the War
Confederate States Presidential Election of 1861
Confiscation Act of 1861
Confiscation Act of 1862
Copperheads
Emancipation Proclamation
Habeas Corpus Act of 1863
Hampton Roads Conference
National Union Party
Radical Republicans
Trent Affair
Union leagues
U.S. Presidential Election of 1864
War Democrats
Other topics
Bibliography
Confederate war finance
Confederate States dollar
Espionage
Confederate Secret Service
Great Revival of 1863
Music
Naming the war
Native Americans
Cherokee
Choctaw
New York City Gold Hoax of 1864
New York City Riot of 1863
Photographers
Richmond Riot of 1863
Sexuality
Supreme Court cases
Tokens
U.S. Sanitary Commission
[show]
v
t
e
Years in South Carolina (1788–present)
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
Retrieved from "https://en.wikipedia.org/w/index.php?title=South_Carolina_in_the_American_Civil_War&oldid=828291871"
Categories:
South Carolina in the American Civil War
Confederate States of America
Hidden categories:
CS1: Julian–Gregorian uncertainty
CS1 maint: Unfit url
Pages incorrectly using the quote template
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
Français
Edit links
This page was last edited on 1 March 2018, at 18:25.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

attrs: colspan class style

value: span

attrs: colspan style

value: small

values:
/wiki/Killed_in_Action
mw-redirect
Killed in Action

values:
/wiki/Armory_(military)
mw-redirect
Armory (military)

values: Confederate States congressional delegations from South Carolina

values: margin: -0.2em 0; font-size:65%; font-weight:normal;

values: background: none; font-size: 145%;padding: 0.15em 0.1em;line-height: 1.2em;

values: padding: 0.2em; border-bottom: 1px solid #ccc;

values:
/wiki/Timeline_of_South_Carolina
mw-redirect
Timeline of South Carolina

values: South Carolina during the American Revolution

values: padding:0.3em 0.4em 0.3em;font-weight:bold;border-top:#aaa 1px solid; border-bottom:#aaa 1px solid;

values: vertical-navbox nowraplinks vcard plainlist

values: Seal of the Confederate States of America

values: North Carolina in the American Civil War

values:
/wiki/East_Tennessee_Convention_of_1861
mw-redirect
East Tennessee Convention of 1861

values: Indian Territory in the American Civil War

values: Template:Confederate states in the American Civil War

values: Template talk:Confederate states in the American Civil War

values: float:right;clear:right;width:22.0em;margin:0 0 1.0em 1.0em;background:#f9f9f9;border:1px solid #aaa;padding:0.2em;border-spacing:0.4em 0;text-align:center;line-height:1.4em;font-size:88%;width: auto; font-size: 100%;

values:
/wiki/Nullification_crisis
mw-redirect
Nullification crisis

values:
/wiki/Slave_power
mw-redirect
Slave power

values: United States presidential election, 1860

values: United States Declaration of Independence

values:
/wiki/Palmetto_flag
mw-redirect
Palmetto flag

values:
/wiki/U.S._Coast_Survey
mw-redirect
U.S. Coast Survey

values: Flags of the Confederate States of America

values:
/wiki/Major_Robert_Anderson
mw-redirect
Major Robert Anderson

values: The Citadel, The Military College of South Carolina

values:
/wiki/50-gun_salute
mw-redirect
50-gun salute

values:
/wiki/54th_Massachusetts_Regiment
mw-redirect
54th Massachusetts Regiment

values:
/wiki/Battle_of_Anderson_County
mw-redirect
Battle of Anderson County

values: Battle of Brattonsville (page does not exist)

values: Battle of Broxton's Bridge (page does not exist)

values: Battle of Gamble's Hotel (The Columns) (page does not exist)

values: Charleston, South Carolina in the American Civil War

values: List of South Carolina Confederate Civil War units

values: List of South Carolina Union Civil War units

values:
nofollow
external text
http://civilwarcauses.org/spratt.htm

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values: Template:South Carolina in the Civil War

values: Template talk:South Carolina in the Civil War

values:
/wiki/File:Flag_of_South_Carolina.svg
image
SC Flag

values:
navbox-image
7
width:1px;padding:0px 0px 0px 2px

values:
/wiki/Battle_of_Pocotaligo
mw-redirect
Battle of Pocotaligo

values: Columbia, South Carolina in the American Civil War

values: Category:South Carolina in the American Civil War

values: nowraplinks collapsible autocollapse navbox-inner

values: Timeline of events leading to the American Civil War

values: History of the United States (1789–1849)

values:
/wiki/Lincoln-Douglas_debates
mw-redirect
Lincoln-Douglas debates

values: Popular sovereignty in the United States

values: Treatment of slaves in the United States

values: nowraplinks collapsible collapsed navbox-subgroup

values: Eastern Theater of the American Civil War

values: Western Theater of the American Civil War

values: Lower Seaboard Theater of the American Civil War

values: Trans-Mississippi Theater of the American Civil War

values: Pacific Coast Theater of the American Civil War

values: Blockade runners of the American Civil War

values: Territory of Arizona (Confederate States)

values: Washington, D.C., in the American Civil War

values: New Mexico Territory in the American Civil War

values:
/wiki/Benjamin_Butler_(politician)
mw-redirect
Benjamin Butler (politician)

values: Thirteenth Amendment to the United States Constitution

values: Fourteenth Amendment to the United States Constitution

values: Fifteenth Amendment to the United States Constitution

values:
/wiki/New_Orleans_riot
mw-redirect
New Orleans riot

values:
/wiki/First_Enforcement_Act_of_1871
mw-redirect
First Enforcement Act of 1871

values:
/wiki/Second_Enforcement_Act_of_1871
mw-redirect
Second Enforcement Act of 1871

values: South Carolina civil disturbances of 1876

values: List of Confederate monuments and memorials

values: Disenfranchisement after the Reconstruction Era

values: List of Union Civil War monuments and memorials

values: List of memorials to the Grand Army of the Republic

values: Removal of Confederate monuments and memorials

values: Roger B. Taney Monument (Annapolis, Maryland)

values: Confederate Soldiers and Sailors Monument

values: Stonewall Jackson and Robert E. Lee Monument

values: Robert E. Lee Monument (Durham, North Carolina)

values: Robert E. Lee Monument (New Orleans, Louisiana)

values: Military Order of the Loyal Legion of the United States

values:
Related_topics
font-size:114%;margin:0 4em
hlist hlist-separated

values: List of weapons in the American Civil War

values: Confederate railroads in the American Civil War

values: Field artillery in the American Civil War

values: List of American Civil War Medal of Honor recipients

values: Military leadership in the American Civil War

values: Official Records of the American Civil War

values: United States Congress Joint Committee on the Conduct of the War

values: Confederate States presidential election, 1861

values: United States presidential election, 1864

values:
/wiki/War_Democrats
mw-redirect
War Democrats

values: Native Americans in the American Civil War

values: Supreme Court cases of the American Civil War

values: nowraplinks hlist collapsible expanded navbox-inner

values: Template talk:South Carolina year nav (page does not exist)

values: List of U.S. states by date of admission to the Union

values: Category:1797 in South Carolina (page does not exist)

values: Category:1811 in South Carolina (page does not exist)

values: Category:1815 in South Carolina (page does not exist)

values: Category:1817 in South Carolina (page does not exist)

values: Category:1819 in South Carolina (page does not exist)

values: Category:1879 in South Carolina (page does not exist)

values: Category:1883 in South Carolina (page does not exist)

values: Category:2021 in South Carolina (page does not exist)

values: Category:2022 in South Carolina (page does not exist)

values: Category:2023 in South Carolina (page does not exist)

values: Category:2024 in South Carolina (page does not exist)

values: Category:2025 in South Carolina (page does not exist)

values: Category:2026 in South Carolina (page does not exist)

values: Category:2027 in South Carolina (page does not exist)

values: Category:2028 in South Carolina (page does not exist)

values: Category:2029 in South Carolina (page does not exist)

values: Category:Pages incorrectly using the quote template

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values: Caroline du Sud durant la guerre de Sécession – French

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-South_Carolina_in_the_American_Civil_War rootpage-South_Carolina_in_the_American_Civil_War skin-vector action-view


text:
Proportional control
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
The fly-ball governor is an early classic example of proportional control. The balls rise as speed increases, which closes the valve, until a balance is achieved between demand and the proportional gain of the linkage and valve.
Proportional control, in engineering and process control, is a type of linear feedback control system in which a correction is applied to the controlled variable which is proportional to the difference between the desired value (set point, SP) and the measured value (process value, PV). Two classic mechanical examples are the toilet bowl float proportioning valve and the fly-ball governor.
The proportional control concept is more complex than an on–off control system like a bi-metallic domestic thermostat, but simpler than a proportional–integral–derivative (PID) control system used in something like an automobile cruise control. On–off control will work where the overall system has a relatively long response time, but can result in instability if the system being controlled has a rapid response time. Proportional control overcomes this by modulating the output to the controlling device, such as a control valve at a level which avoids instability, but applies correction as fast as practicable by applying the optimum quantity of proportional gain.
A drawback of proportional control is that it cannot eliminate the residual SP − PV error in processes with compensation e.g. temperature control,[1] as it requires an error to generate a proportional output. To overcome this the PI controller was devised, which uses a proportional term (P) to remove the gross error, and an integral term (I) to eliminate the residual offset error by integrating the error over time to produce an "I" component for the controller output.
Contents
1 Theory
2 Development of control block diagrams
3 Offset error
4 Proportional band
5 Advantages
6 References
7 External links
Theory[edit]
In the proportional control algorithm, the controller output is proportional to the error signal, which is the difference between the setpoint and the process variable. In other words, the output of a proportional controller is the multiplication product of the error signal and the proportional gain.
This can be mathematically expressed as,
P o u t = K p e ( t ) + p 0 {\displaystyle P_{\mathrm {out} }=K_{p}\,{e(t)+p0}}
where
p 0 {\displaystyle p0} : Controller output with zero error.
P o u t {\displaystyle P_{\mathrm {out} }} : Output of the proportional controller
K p {\displaystyle K_{p}} : Proportional gain
e ( t ) {\displaystyle e(t)} : Instantaneous process error at time t. e ( t ) = S P − P V {\displaystyle e(t)=SP-PV}
SP: Set point
PV: Process variable
Constraints: In a real plant, actuators have physical limitations that can be expressed as constraints on P o u t {\displaystyle P_{\mathrm {out} }} . For example, P o u t {\displaystyle P_{\mathrm {out} }} may be bounded between −1 and +1 if those are the maximum output limits.
Qualifications: It is preferable to express K p {\displaystyle K_{p}} as a unitless number. To do this, we can express e ( t ) {\displaystyle e(t)} as a ratio with the span of the instrument. This span is in the same units as error (e.g. C degrees) so the ratio has no units.
Development of control block diagrams[edit]
Simple feedback control loop2
Proportional control dictates g c = k c {\displaystyle {\mathit {g_{c}=k_{c}}}} . From the block diagram shown, assume that r, the setpoint, is the flowrate into a tank and e is error, which is the difference between setpoint and measured process output. g p , {\displaystyle {\mathit {g_{p}}},} is process transfer function; the input into the block is flow rate and output is tank level.
The output as a function of the setpoint, r, is known as the closed-loop transfer function. g c l = g p g c 1 + g p g c , {\displaystyle {\mathit {g_{cl}}}={\frac {\mathit {g_{p}g_{c}}}{1+g_{p}g_{c}}},} If the poles of g c l , {\displaystyle {\mathit {g_{cl}}},} are stable, then the closed-loop system is stable.
Offset error[edit]
Flow control loop. If only a proportional controller, then there's always an offset between SP and PV.
Proportional control cannot eliminate the offset error, which is the difference between the desired value and the actual value, SP − PV error, as it requires an error to generate an output. When a disturbance (deviation from existing state) occurs in the process value being controlled, any corrective control action, based purely on Proportional Control, will always leave out the error between the next steady state and the desired setpoint, and result in a residual error called the offset error. This error will increase as greater process demand is put on the system, or by increasing the set point.
Consider an object suspended by a spring as a simple proportional control. The spring will attempt to maintain the object in a certain location despite disturbances which may temporarily displace it. Hooke's law tells us that the spring applies a corrective force that is proportional to the object's displacement. While this will tend to hold the object in a particular location, the absolute resting location of the object will vary if its mass is changed. This difference in resting location is the offset error.
Imagine the same spring and object in a weightless environment. In this case, the spring will tend to hold the object in the same location regardless of its mass. There is no offset error in this case because the proportional action is not working against anything in the steady state.
Proportional band[edit]
The proportional band is the band of controller output over which the final control element (a control valve, for instance) will move from one extreme to another. Mathematically, it can be expressed as:
P B = 100 K p {\displaystyle PB={\frac {100}{K_{p}}}\ }
So if K p {\displaystyle K_{p}} , the proportional gain, is very high, the proportional band is very small, which means that the band of controller output over which the final control element will go from minimum to maximum (or vice versa) is very small. This is the case with on–off controllers, where K p {\displaystyle K_{p}} is very high and hence, for even a small error, the controller output is driven from one extreme to another.
Advantages[edit]
The clear advantage of proportional over on–off control can be demonstrated by car speed control. An analogy to on–off control is driving a car by applying either full power or no power and varying the duty cycle, to control speed. The power would be on until the target speed is reached, and then the power would be removed, so the car reduces speed. When the speed falls below the target, with a certain hysteresis, full power would again be applied. It can be seen that this would obviously result in poor control and large variations in speed. The more powerful the engine; the greater the instability, the heavier the car; the greater the stability. Stability may be expressed as correlating to the power-to-weight ratio of the vehicle.
In proportional control, the power output is always proportional to the (actual versus target speed) error. If the car is at target speed and the speed increases slightly due to a falling gradient, the power is reduced slightly, or in proportion to the change in error, so that the car reduces speed gradually and reaches the new target point with very little, if any, "overshoot", which is much smoother control than on–off control. In practice, PID controllers are used for this and the large number of control processes that require more response control than proportional alone.
References[edit]
Jump up ^ JUMO. "JUMO Campus - Control Engineering Basic principles and tips for practitioners". campus.jumo.de. Retrieved 2017-12-06.
Bequette, B. Wayne. Process Control: Modeling, Design, and Simulation. Prentice Hall PTR, 2010. [1]
External links[edit]
Proportional control compared to on–off or bang–bang control
Retrieved from "https://en.wikipedia.org/w/index.php?title=Proportional_control&oldid=843359190"
Categories:
Classical control theory
Control theory
Control devices
Control engineering
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
Deutsch
Español
Nederlands
中文
Edit links
This page was last edited on 28 May 2018, at 16:46 (UTC).
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

attrs: class href

values: mw-jump-link #mw-head

values: mw-jump-link #p-search

value: img

attrs: alt src width height class srcset data-file-width data-file-height

attrs: href class

attrs: href class title

attrs: href title

attrs: class style

value: b

value: p

values:
/wiki/On%E2%80%93off_control
mw-redirect
On–off control

values:
/wiki/PI_controller
mw-redirect
PI controller

values: checkbox button toctogglecheckbox toctogglecheckbox display:none

values: vertical-align: -1.005ex; width:19.523ex; height:3.009ex;

values: vertical-align: -0.671ex; margin-left: -0.089ex; width:2.421ex; height:2.509ex;

values: vertical-align: -0.671ex; width:4.1ex; height:2.509ex;

values: vertical-align: -1.005ex; width:3.032ex; height:2.843ex;

values: vertical-align: -0.838ex; width:3.732ex; height:2.843ex;

values: vertical-align: -0.838ex; width:16.449ex; height:2.843ex;

values: Edit section: Development of control block diagrams

values: vertical-align: -0.671ex; width:7.189ex; height:2.509ex;

values: vertical-align: -1.005ex; width:2.789ex; height:2.343ex;

values: vertical-align: -2.505ex; width:15.285ex; height:5.676ex;

values: vertical-align: -0.671ex; width:3.126ex; height:2.009ex;

values: vertical-align: -2.505ex; width:11.512ex; height:5.843ex;

values:
catlinks mw-normal-catlinks
catlinks mw-normal-catlinks
interface

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Proportional_control
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
https://de.wikipedia.org/wiki/P-Glied
P-Glied – German
de
de
interlanguage-link-target

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Proportional_control rootpage-Proportional_control skin-vector action-view