Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 236)

Preface MicroLogix 1000 Programmable Controllers User Manual
12–22
High-Speed Counter Reset Accumulator (RAC)
This instruction allows you to write a specific value to the hardware accumulator
and image accumulator.
The Counter referenced by this instruction has the same address as the HSC
instruction counter and is fixed at C5:0.
Entering Parameters
Enter the following parameter when programming this instruction:
•
Source represents the value that is loaded to the accumulator. The source can
be a constant or an address.
Operation
Execution of the RAC:
•
removes pending high-speed counter interrupts
•
resets the PE, LS, OV, UN, and DN status bits
•
loads a new accumulator value to the hardware and instruction image
•
loads the instruction high preset to the hardware high preset (if the high-speed
counter is configured as an Up Counter)
•
resets the IL, IH, IN, or IV status bits
The source can be a constant or any integer element in files 0–7. The hardware and
instruction accumulators are updated with the new accumulator value immediately
upon instruction execution.
You can have more than one RAC instruction per program referencing the same
source or different sources.
Execution Times
(µ
sec
)
when:
True False
56.00 6.00
RAC
RESET TO ACCUM VALUE
Counter
C5:0
Source