Set Coil, Reset Coil - GE PACSystems RX7i Cpu Programmer's Reference Manual

Chapter 4. Ladder Diagram (LD) Programming
4.3.3

Set Coil, Reset Coil

Set Coil and Reset Coil with a retentive variable
assigned
The SET and RESET coils can be used to keep (i.e. latch) the state of a reference either ON or OFF.
When a SET coil receives power flow, it sets its discrete reference ON. When a SET coil does not
receive power flow, it does not change the value of its discrete reference. Therefore, whether or not
the coil itself continues to receive power flow, the reference stays ON until the reference is reset by
other logic, such as a RESET coil.
When a RESET coil receives power flow, it resets a discrete reference to OFF. When a RESET coil does
not receive power flow, it does not change the value of its discrete reference. Therefore, its reference
remains OFF until it is set ON by other logic, such as a SET coil.
The last solved SET coil or RESET coil of a pair takes precedence.
The SET and RESET coils can be assigned a retentive variable or a non-retentive variable.
Valid memory areas: %I, %Q, %M, %T, %SA - %SC, and %G. Symbolic discrete variables are permitted.
Bit-in-word references on any word-oriented memory except %AI, including symbolic non-discrete
memory, are also permitted.
Example of Set Coil, Reset Coil
86 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
Set Coil and Reset Coil with a non-retentive
variable assigned
SET / RESET coils write an undefined result to the
transition bit for the given reference. This result differs
from that written by Series 90-70 CPUs and could
change for future PACSystems CPU models.
Because they write an undefined result to transition
bits, do not use SET or RESET coils with references used
on POSCON or NEGCON transition contacts.
The coil represented by E1 is turned ON when reference E2 or
E6 is ON and is turned OFF when reference E5 or E3 is ON.
Warning
GFK-2950C