Siemens SIMATIC S7-200 - IEC Timer Instructions; On-Delay Timer Function Block; Off-Delay Timer

IEC 1131-3 Instructions
10-11
S7-200 Programmable Controller System Manual
A5E00066097-02
10.3 IEC Timer Instructions
Table 10-2 gives page references for the non-standard IEC Timer instructions.
Table 10-2 Non-Standard IEC Timer Instructions
Description
Page
On-Delay Retentive Timer Instruction 9-15
On-Delay Retentive Timer Function Block 9-15
On-Delay Timer Function Block
The On-Delay Timer function block times up to the
preset value when the enabling input (IN) becomes true.
When the elapsed time (ET) is greater than or equal to
the Preset Time (PT), the timer output bit (Q) turns on.
The output bit resets when the enabling input goes false.
When the preset time (PT) is reached, timing stops and
the timer is disabled.
Inputs/Outputs Operands Data Types
IN (LAD) Power Flow BOOL
IN (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
PT (LAD & FBD) VW, IW, QW, MW, SMW, LW, SW, AIW, AC, Constant, *VD, *AC, *LD INT
Q (LAD & FBD) I, Q, M, SM, V, S, L BOOL
ET (LAD & FBD) VW, IW, QW, MW, SMW, LW, SW, AQW, AC, *VD, *AC, *LD INT
Txxx Constant, refer to Table 10-3, page 10-12. TON
Off-Delay Timer
The Off-Delay Timer function block 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) makes the transition to true. If the enabling
input (IN) makes the transition to false for a period of time shorter than the preset
time (PT), the output bit remains true.
For information about timer numbers and resolutions, refer to Table 10-3.
L
A
D
TON
IN
Txxx
F
B
D
PT Q
ET
222 224
✓✓✓
221 224
✓
L
A
D
TOF
IN
Txxx
F
B
D
Q
ET
222 224
✓✓✓
221
PT
226
✓