GE VersaMax PLC User Manual page 177

E1
E2
Instruction Set Reference
For public disclosure
10.7.2.6 Positive Transition Coil
If the reference associated with a positive transition coil was OFF , when the coil receives
power flow it is set to ON until the next time the coil is executed. (If the rung containing
the coil is skipped on subsequent sweeps, it will remain ON.) This coil can be used as a
one-shot.
Do not write from external devices (e.g., PCM, programmer, ADS, etc.) to references
used on positive transition coils since it will destroy the one-shot nature of these coils.
Transitional coils can be used with references from either retentive or non-retentive
memory (%Q, %M, %T, %G, %SA, %SB, or %SC).
10.7.2.7 Negative Transition Coil
If the reference associated with this coil is OFF, when the coil stops receiving power flow
the reference is set to ON until the next time the coil is executed.
Do not write from external devices to references used on negative transition coils since it
will destroy the one-shot nature of these coils.
Transitional coils can be used with references from either retentive or non-retentive
memory (%Q, %M, %T, %G, %SA, %SB, or %SC).
10.7.2.8 Example
In the example, when reference E1 goes from OFF to ON, coils E2 and E3 receive power
flow, turning E2 ON for one logic sweep. When E2 goes from ON to OFF, power flow is
removed from E2 and E3, turning coil E3 ON for one sweep.
10.7.2.9
SET and RESET are non-retentive coils that can be used to keep ("latch") the state of a
reference either ON or OFF. When a SET coil receives power flow, its reference stays ON
(whether or not the coil itself receives power flow) until the reference is reset by another
coil.
10.7.2.10 RESET Coil
The RESET coil sets a discrete reference OFF if the coil receives power flow. The
reference remains OFF until the reference is set by another coil. The last-solved SET coil
or RESET coil of a pair takes precedence.
Example
In the example, the coil represented by E1 is turned ON whenever reference E2 or E6 is
ON. The coil represented by E1 is turned OFF whenever reference E5 or E3 is ON.
E2
(P)
E3
(N)
GFK-1503E User Manual 177