Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 109)

Using Basic Instructions
6–11
Timer On-Delay (TON)
Use the TON instruction to delay the turning on or off of an output. The TON
instruction begins to count timebase intervals when rung conditions become true.
As long as rung conditions remain true, the timer increments its accumulated value
(ACC) each scan until it reaches the preset value (PRE). The accumulated value is
reset when rung conditions go false, 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)
accumulated value is equal
to or greater than the preset
value
rung conditions go false
Timer Enable Bit EN (bit 14) rung conditions are true rung conditions go false
Timer Timing Bit TT (bit 15)
rung conditions are true and
the accumulated value is less
than the preset value
rung conditions go false or
when the done bit is set
When the controller changes from the REM Run or REM Test mode to the
REM Program mode or user power is lost while the instruction is timing but has not
reached its preset value, the following occurs:
•
Timer Enable (EN) bit remains set.
•
Timer Timing (TT) bit remains set.
•
Accumulated value (ACC) remains the same.
On returning to the REM Run or REM Test mode, the following can happen:
Condition Result
If the rung is true:
EN bit remains set.
TT bit remains set.
ACC value is reset.
If the rung is false:
EN bit is reset.
TT bit is reset.
ACC value is reset.
Programming
Execution Times
(
µ
sec) when:
True False
38.34 30.38
(EN)
(DN)
TON
TIMER ON DELAY
Timer
Time Base
Preset
Accum