User Manual
Chapter 11
GFK-1503F
Jan 2020
The Service Request Function
180
Figure 177
Example of SVCREQ 1
In this example, if contact OV_SWP is set, the Constant SweepTimer is read, the timer is
increased by two milliseconds, and the new timer value is sent back to the PLC. The
parameter block is in local memory at location %R0050. Because the MOVE and ADD
functions require three horizontal contact positions, the example logic uses discrete
internal coil %M00001 as a temporary location to hold the successful result of the first rung
line. On any sweep in which OV_SWP is not set, %M00001 is turned off.
Figure 178
11.4
SVCREQ 2: Read Window Times
SVCREQ 2 can be used to read the times of the programmer communications window and
the system communications window. These windows can operate in Limited or Run to
Completion Mode.
Mode Name
Value
Description
Limited Mode
0
The execution time of the window is limited to 6ms. The window
terminates when it has no more tasks to complete or after 6ms
elapses.
Run to Completion
Mode
2
Regardless of the time assigned to a window, it runs until all tasks
within that window are completed (up to 400ms).
A window is disabled when the time value is zero.