Timers - Siemens SINUMERIK 840Di sl Function Manual

Detailed description
2.3 Special real-time variables for synchronized actions
2.3.2

Timers

The system variable $AC_TIMER[n] permits actions to be started after
defined periods of delay.
Definition
Data type: REAL
n: Number of timer variable
Unit: Second
The number of available timer variables is determined via the machine data
MD28258 $MC_MM_NUM_AC_TIMER.
Setting timers
The incrementing of a timer variable is started by means of value assignment:
$AC_TIMER[n]=value
n: Number of time variable
value: Start value (normally 0)
Stopping timers
Incrementation of a timer variable can be stopped by assigning a negative value:
$AC_TIMER[n]=-1
Reading timers
The current timer value can be read whether the timer variable is running or has been
stopped. After a timer variable has been stopped through the assignment of -1, the current
time value remains stored and can be read.
Example
Output of an actual value via analog output 500 ms after detection of a digital input:
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
30
; Reset and start timer
Function Manual, 11/2006, 6FC5397-5BP10-2BA0
Synchronized actions