Allen-Bradley Logix5000 Reference Manual page 134

Chapter 3 Timer and Counter Instructions (TON, TOF, RTO, TONR, TOFR, RTOR, CTU, CTD, CTUD, RES)
Input Parameter Data Type
Status DINT
InstructFault (Status.0) BOOL
PresetInv (Status.1) BOOL
Description:
Timer Accumulated Value (ACC)
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Description
Status of the function block.
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.
The preset value is invalid.
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.
TimerEnable
Enable Bit (EN)
Timer Timing Bit (TT)
Timer Done Bit (DN)
Preset
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)
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
OFF Delay
0
Timer did not reach PRE value
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