Allen-Bradley Logix5000 Reference Manual

134 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 3 Timer and Counter Instructions (TON, TOF, RTO, TONR, TOFR, RTOR, CTU, CTD, CTUD, RES)
Description: The TOFR instruction accumulates time until the following occurs:
· TOFR instruction is disabled
· ACC ≥ PRE
The time base is always 1 ms. For example, for a two-second timer, enter 2000 for
the PRE value.
Set the Reset input parameter to reset the instruction. If TimerEnable is cleared
when Reset is set, the TOFR instruction does not begin timing again when Reset
is cleared.
A timer runs by subtracting the time of its last scan from the time now:
ACC = ACC + (current_time - last_time_scanned)
Status DINT Status of the function block.
InstructFault (Status.0) BOOL The instruction detected one of the following execution errors. This is not a minor or major controller
error. Check the remaining status bits to determine what occurred.
PresetInv (Status.1) BOOL The preset value is invalid.
Input Parameter Data Type Description
TimerEnable
Enable Bit (EN)
Timer Done Bit (DN)
Timer Accumulated Value (ACC)
Timer Timing Bit (TT)
0
OFF Delay
16650
Timer did not reach PRE value
Preset

Allen-Bradley Logix5000 Specifications

General

Brand	Allen-Bradley
Model	Logix5000
Category	Controller
Language	English