Siemens SINUMERIK 828D Function Manual page 29

Function
Starting
A timer is started by assigning a value ≥ 0:
$AC_TIMER[<index>] = <starting value>; with starting value ≥ 0
Incrementing
The value of the timer is incremented by the duration of the set interpolation cycle (MD10071
IPO_CYCLE_TIME) each interpolation cycle.
$AC_TIMER[<index>] += <interpolation cycle>
Stopping
A timer is stopped by assigning a value < 0:
$AC_TIMER[<index>] = <stopping value>; with stopping value < 0
When a stopping value is assigned, only the further incrementing of the timer is stopped. The
stopping value is not assigned. After the timer is stopped, the last valid value is retained and
can still be read.
Note
The current value of a timer can be be read when the timer is running or stopped.
Example
Output the actual value of the X axis as voltage value via analog output $A_OUTA[3], 500
ms after the detection of digital input $A_IN[1]:
Program code
WHEN $A_IN[1] == 1 DO $AC_TIMER[1]=0
WHEN $AC_TIMER[1]>=0.5 DO $A_OUTA[3]=$AA_IM[X] $AC_TIMER[1]=-1
Synchronized actions
Function Manual, 07/2012, 6FC5397-5BP40-3BA0
2.3 System variables for synchronized actions
Comment
; Start time, starting value 0
Detailed description
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