Publication 1766-RM001A-EN-P - October 2008
Timer and Counter Instructions
179
TON - Timer, On-Delay
Instruction Type: output
Use the TON instruction to delay turning on an output. The TON
instruction begins to count time base intervals when rung conditions
become true. As long as rung conditions remain true, the timer increments
its accumulator until the preset value is reached. When the accumulator
equals the preset, timing stops.
The accumulator is reset (0) when rung conditions go false, regardless of
whether the timer has timed out. TON timers are reset on power cycles
and mode changes.
Timer instructions use the following control and status bits:
EN
DN
TON
Timer On Delay
Timer
T4:0
Time Base
1.0
Preset
0<
Accum
0<
TON
Execution Time for the TON Instructions
Controller
When Rung Is:
True
False
MicroLogix 1400
2.0338 µs (DN=0)
1.2608 µs (DN=1)
0.8608 µs (DN=0)
Timer Control and Status Bits, Timer Word 0 (Data File 4 is configured as a timer file for this example.)
Bit
Is Set When:
And Remains Set Until One of the
Following Occurs:
bit 13 - T4:0/DN
DN - timer done
accumulated value
≥
preset value
rung state goes false
bit 14 - T4:0/TT
TT - timer timing
rung state is true and accumulated
value < preset value
•
rung state goes false
•
DN bit is set
bit15 - T4:0/EN
EN - timer enable
rung state is true
rung state goes false
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