User manual

IEC61131 User and Reference Manual
April 22, 2008
385
Coil and Status Registers
Coil and status registers contain one bit of information, that is, whether a signal is off or on.
Writing any non-zero value to the register turns the bit on. Writing zero to the register turns
the bit off. If the register is assigned to an I/O module, the bit status is written to the module
output hardware or parameter.
Reading a coil or status register returns –1 if the bit is on, or 0 if the bit is off. The stored
value is returned from general purpose registers. The I/O module point status is returned
from assigned registers.