User guide

Interrupts – 5/02 Processor Only
Chapter 30
Understanding Selectable Timed
30–8
The STS instruction can be used to condition the start of the STI timer upon
entering the Run mode – rather than starting automatically. It can also be
used to set up or change the file number or setpoint/frequency of the STI
routine that will be executed when the STI timer expires.
This instruction is not required to configure a basic STI interrupt application.
Selectable Timed Start STS Output Instruction
STS
SELECTABLE TIMED START
File 3
Time (x10 ms) 30
(STS)
HHT Ladder Display:
HHT Zoom Display:
Ladder Diagrams and APS Displays:
(monitor mode)
F1 F2 F3 F4 F5
ZOOM on STS –(STS)– 2.9.0.0.1
NAME: SELECTABLE TIMED START
FILE: 3 3
TIME: 30 30
EDT_DAT
STS Selectable Timed Start Immediately – The STS instruction requires
you to enter two parameters, the STI file number and the STI setpoint. Upon
a true execution of the rung, this instruction will enter the file number and
setpoint/frequency in the status file (S:31, S:30), overwriting the existing
data. At the same time, the STI timer is reset and begins timing; at timeout,
the STI subroutine execution occurs. When the rung goes false, the STI
function remains enabled at the setpoint and file number you’ve entered in
the STS instruction.
STS Instruction