Monitoring - Manual - Monitor - The SIMATIC Monitor. Enables you to monitor global variables on your PLC. - Monitor (mon),tool

Monitor CLI Tool (mon)

Portfolio
SIMATIC AX
Product
Monitor
Software version
1.6.5
Edition
01/2025
Language
English (original)
Package Name
@ax/mon

The monitor is able to display values for global symbolic variables and absolute addresses.
The information what to show is passed by this format to the monitor tool:

<VariableNameOfElementaryDataType>
<SymbolNameOfArray>
<SymbolNameOfArray>[arrayIndex]
<SymbolNameOfArray>[arrayIndex, *, arrayIndex]
<InstanceNameOfStructuredType>
<InstanceNameOfStructuredType>.<SymbolNameOfField>
<InstanceNameOfClass>
<InstanceNameOfClass>.<MemberName>
<AbsoluteAddress>:<ElementaryDataType>
# this is a comment

This format can be passed in two ways to the mon tool. Either directly as a value for the command line parameter --symbols or inside a monitor file. This file is then passed as the value for the argument --file.

The output can also received in multiple ways. There is an human readable format which is the default. It prints all given variables to a table. When using it in combination with the flag --continuously the table will be updated every 200 ms.
The other way is to pass the parameter --output json. This will result in receiving json objects.