5.20 Control and monitoring of variables with test functions
n
For troubleshooting purposes and to display the status of certain variables you can
access certain test functions via the menu item
Debug
of the Siemens SIMATIC Man-
ager.
n
The status of the operands and the RLO can be displayed by means of the test func-
tion
‘Debug
è
Monitor’
.
n
The status of the operands and the RLO can be displayed by means of the test func-
tion
‘PLC
è
Monitor/Modify Variables’
.
n
This test function displays the current status and the RLO of the different operands
while the program is being executed.
n
It is also possible to enter corrections to the program.
n
The processing of the states may be interrupted by means of jump commands or by
timer and process-related interrupts.
n
At the breakpoint the CPU stops collecting data for the status display and instead of
the required data it only provides the PG with data containing the value 0.
n
The interruption of the processing of statuses does not change the execution of the
program. It only shows that the data displayed is no longer valid.
When using the test function "Monitor" the PLC must be in RUN mode!
For this reason, jumps or time and process alarms can result in the value displayed
during program execution remaining at 0 for the items below:
n
the result of the logical operation RLO
n
Status / ACCU 1
n
ACCU 2
n
Condition byte
n
absolute memory address SAZ. In this case SAZ is followed by a "?".
Overview
‘Debug
è
Monitor’
System 300S
+
Deployment CPU 315-4PN23
Control and monitoring of variables with test functions
HB140 | CPU | 315-4PN23 | en | 18-02
73
