def read_coils(addr, ncoils)
      query("\x1" + addr.to_word + ncoils.to_word).unpack_bits[0..ncoils-1]
    end
def read_coils(addr, ncoils)
      query("\x1" + addr.to_word + ncoils.to_word).unpack_bits[0..ncoils-1]
    end
Read coils

 @example
  read_coils(addr, ncoils) => [1, 0, ..]

 @param [Integer] addr address first coil
 @param [Integer] ncoils number coils
 @return [Array] coils