Program instructions
7.17 Timer
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
377
7.17
Timer
7.17.1
Timer instructions
LAD / FBD
STL
Description
TON Txxx, PT
Use TON On-delay timers for a timing a single time interval.
TONR Txxx, PT
Use TONR On-delay retentive timers for accumulating the time value of many timed
intervals.
TOF Txxx, PT
Use the TOF Off-delay timer for extending a time interval past an OFF (or FALSE)
condition, such as a delay time for cooling a motor.
Input / output
Data type
Operand
Txxx
WORD
Timer number (T0 to T255)
IN
BOOL
I, Q, V, M, SM, S, T, C, L, Power Flow
PT
INT
IW, QW, VW, MW, SMW, SW, T, C, LW, AC, AIW, *VD, *LD, *AC, Constant
Timer resolution
TON, TONR, and TOF timers are available in three resolutions. The resolution is determined
by the timer number, as shown below. Each unit 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 of elapsed time.
Your Txxx timer number assignment determines the resolution of the timer. When a valid
timer number is assigned, the resolution is displayed in LAD or FBD timer boxes.