4-6Series 90-30/20/Micro Programmable Controllers Reference Manual – September 1998 GFK-0467K
4
SET Coil —(S) —SET and RESET are non-retentive coils that can be used to keep (“latch”) the state of a reference
(e.g., E1) 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.
SET coils write an undefined result to the transition bit for the given reference. (Refer to the
information on “Transitions and Overrides” in chapter 2, “System Operation.”)
RESET Coil —(R)— The RESET coil sets a discrete reference OFF if the coil receives power flow. The reference
remains OFF until the reference is reset by another coil. The last-solved SET coil or RESET coil of
a pair takes precedence.
RESET coils write an undefined result to the transition bit for the given reference. (Refer to the
information on “Transitions and Overrides” in chapter 2, “System Operation.”)
Example:
In the following 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 E1
|——| |——+——————————————————————————————————————————————————————————————————(S)—
| |
| E6 |
|——| |——+
|
| E5 E1
|——| |——+——————————————————————————————————————————————————————————————————(R)—
| |
| E3 |
|——| |——+
|
Note
When the level of coil checking is SINGLE, you can use a specific %M or %Q
reference with only one Coil, but you can use it with one SET Coil and one
RESET Coil simultaneously. When the level of coil checking is WARN
MULTIPLE or MULTIPLE, then each reference can be used with multiple Coils,
SET Coils, and RESET Coils. With multiple usage, a reference could be turned
ON by either a SET Coil or a normal Coil and could be turned OFF by a RESET
Coil or by a normal Coil.