I’m working on a WAGO PFC100 with CODESYS. During development everything worked fine, but in the final stage I set several variables to PERSISTENT RETAIN.
When I go online, most of these persistent variables cannot be monitored. Instead, I see:
<Value of the expression cannot be retrieved>
Interestingly, a few variables do show their values correctly, but the majority do not.
The variables are not used as pointers or in any unusual way.
The application compiles and runs without errors.
Has anyone experienced this before? Is this a known issue with PFC100 or CODESYS? Any ideas on what could cause this behavior?
It is a known issue. It only happens with CODESYS and Wago controllers and the Persistent Variables. It seems related to using 64 bit variables in the PV list (e.g. LREAL). Internally in the PLC everything works okay. It is just a monitoring issue.
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Hi everyone,
I’m working on a WAGO PFC100 with CODESYS. During development everything worked fine, but in the final stage I set several variables to PERSISTENT RETAIN.
When I go online, most of these persistent variables cannot be monitored. Instead, I see:
<Value of the expression cannot be retrieved>Interestingly, a few variables do show their values correctly, but the majority do not.
The variables are not used as pointers or in any unusual way.
The application compiles and runs without errors.
Has anyone experienced this before? Is this a known issue with PFC100 or CODESYS? Any ideas on what could cause this behavior?
Thanks in advance!
Jasper
It is a known issue. It only happens with CODESYS and Wago controllers and the Persistent Variables. It seems related to using 64 bit variables in the PV list (e.g. LREAL). Internally in the PLC everything works okay. It is just a monitoring issue.