Off-Delay Timer Timers

Inputs/Outputs Operands Data Types
Txxx Constant (T32 T63, T97 T255) TOF
IN (LAD) Power Flow BOOL
IN (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
PT VW, IW, QW, MW, SW, SMW, LW, AIW, AC, Constant, *VD, *AC, *LD INT
Q I, Q, M, SM, V, S, L BOOL
ET VW, IW, QW, MW, SW, SMW, LW, AQW, AC, *VD, *AC, *LD INT

Memory Ranges ENO Errors Instruction Support for S7-200 CPUs SIMATIC/International Mnemonics
The Off-Delay Timer (TOF) is used to delay the setting of an output false for a fixed period of time after the input goes false. It times up to the preset value when the enabling input (IN) goes false. When the elapsed time (ET) is greater than or equal to the preset time (PT), the timer output bit (Q) turns on.

Once the preset is reached, the timer output bit turns false and the elapsed time is maintained until the enabling input (IN) transitions to true. If the enabling input (IN) transitions to false for a period of time shorter than the preset time (PT), the output bit remains true.

TON, TOF, and TP timers are available in three resolutions. The resolution is determined by the timer number as shown in the chart below. Each count of the current value is a multiple of the time base. For example, a count of 50 on a 10-ms timer represents 500 ms.

Timer Type Resolution Maximum Value Timer Number

TON, TOF, 1 ms 32.767 s T32, T96

TP 10 ms 327.67 s T33-T36, T97-T100

100 ms 3276.7 s T37-T63, T101-T255


Note:

You cannot share the same timer numbers for TOF, TP, and TON. For example, you cannot have both a TON T32 and a TOF T32.

Example: