Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 118)

Preface MicroLogix 1000 Programmable Controllers User Manual
6–20
Reset (RES)
Use a RES instruction to reset a timer or counter. When the RES instruction is
executed, it resets the data having the same address as the RES instruction.
Using a RES instruction for a: The controller resets the:
Timer
(Do not use a RES instruction
with a TOF.) ACC value to 0
DN bit
TT bit
EN bit
Counter ACC value to 0
OV bit
UN bit
DN bit
CU bit
CD bit
Control POS value to 0
EN bit
EU bit
DN bit
EM bit
ER bit
UL bit
IN and FD go to last state
Note If using this instruction to reset the HSC accumulator, see page 12–21.
When resetting a counter, if the RES instruction is enabled and the counter rung is
enabled, the CU or CD bit is reset.
If the counter preset value is negative, the RES instruction sets the accumulated
value to zero. This in turn causes the done bit to be set by a count down or count up
instruction.
Because the RES instruction resets the accumulated value, and the done,
timing, and enabled bits, do not use the RES instruction to reset a timer
address used in a TOF instruction. Otherwise, unpredictable machine
operation or injury to personnel may occur.
Execution Times
(
µ
sec) when:
True False
15.19 4.25
(RES)