Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 137)

Chapter 8
Using Basic Instructions
8–18
Use the TOF instruction to delay turning on or off an output. The TOF
instruction begins to count timebase intervals when the rung makes a
true-to-false transition. As long as rung conditions remain false, the timer
increments its accumulated value (ACC) each scan until it reaches the preset
value (PRE). The controller resets the accumulated value when rung
conditions go true regardless of whether the timer has timed out.
Using Status Bits
This Bit Is Set When
And Remains Set Until One
of the Following
Timer Done Bit DN (bit 13) rung conditions are true rung conditions go false and
the accumulated value is
greater than or equal to the
preset value
Timer Timing Bit TT (bit 14) rung conditions are false and
the accumulated value is less
than the preset value rung conditions go true or
when the done bit is reset
Timer Enable Bit EN (bit 15) rung conditions are true rung conditions go false
Entering the Instruction
You enter the instruction from within the program monitor functional area.
P 0 0 0 T O F A D D R
T 1
P 0 0 0 T O F P R E
* * * 1 2 0
P 0 0 0 T O F A C C
* * * * * 0
P 0 0 0 T O F B A S E
0 . 0 1 S E C
(EN)
(DN)
TOF
TIMER OFF DELAY
Timer
T4:1
Time Base 0.01
Preset 120
Accum 0
Execution Times (
µ
sec) when:
True False
39.42 31.65
Ladder representation:
Timer Off-Delay (TOF)
FUN ENT
To enter the function code, press:
1