Siemens SIMATIC S7 System Manual page 378

Program instructions
7.17 Timer
Timer number and resolution options
Timer type
TON, TOF
TONR
Note
Avoid timer number conflicts
You cannot use the same timer number for both a TON and TOF timer. For example, you
cannot have both a TON T32 and a TOF T32.
Note
To guarantee a minimum time interval, increase the preset value (PV) by 1.
For example: To ensure a minimum timed interval of at least 2100 ms for a 100-ms timer, set
the PV to 22.
TON and TONR timer operation
The TON and TONR instructions begin timing when the enabling input IN is ON. When the
current value is equal to or greater than the preset time, the timer bit is set ON.
● The current value of a TON timer is cleared when the enabling input is OFF.
● The current value of the TONR timer is maintained when the enabling input is OFF. You
can use the TONR timer to accumulate time when the input IN is ON. Use the Reset
instruction (R) to clear the current value of the TONR.
● Both the TON and the TONR timers continue timing after the preset time is reached, and
they stop timing at the maximum value of 32,767.
378
Resolution
1 ms
10 ms
100 ms
1 ms
10 ms
100 ms
Maximum value
32.767 s
327.67 s
3276.7 s
32.767 s
327.67 s
3276.7 s
System Manual, V2.3, 07/2017, A5E03822230-AF
Timer number
T32, T96
T33-T36, T97-T100
T37-T63, T101-T255
T0, T64
T1-T4, T65-T68
T5-T31, T69-T95
S7-200 SMART