A colleague presented the following,
“Does the CM CanOpen need to be in NMT Operational mode to be able to read and write the data? If yes, how do I switch this to Operational mode?”
the CM module is able to exchange process image data when itis operational
- additional condition for TPDOs of the CM module:
minimum one slave must be operational
note:
only successfully booted slaves (whose configuration was successful) can be set to operational
the CM module swichtes automatically to operational when the network initialization has been finished and the PLC is RUN
“I am having trouble reading / writing the data from/to the CM CanOpen module. I am using the RDREC and WRREC functions is TIA Portal software. I have given a correct hardware ID. I am able to read some data with the RDREC but this not the data I expect to read. How to determine what value the variable Index should have in RDREC?”
the data format of the exchanged data is Little Endian:
- 16 bit / 32 bit values must be swapped after reception / before transmission by the PLC
the order and the offset of a value in the uploaded / downloaded byte stream depends of the layout of the process image in the Configuration Studio
- see the description of the processing of the PI data by the CANopen demo
“With WRREC, I am unable to write any data and I am getting a error every time. The STATUS variable has a value of 16#C080_A300 in it. Any idea what this means? Is there an example of the RDREC & WRREC I can see to understand how to use these?
16#C080_A300: general backplane communication error:”
- please send the TIA project: it must be checked
attached the CANopen demo for TIA V13. it consists of
- a demo configuration of the Configuration Studio
- TIA V13 CANopen demo whose exchange of PI data is based on the layout of the process image in the demo configuration of the Configuration Studio
- please read the description of the demo:
it provides musch more information than the manual
My CM CanOpen module is stuck in NMT “Pre-Operational” mode. “RUN” LED is blinking. I am not sure how to change the mode to Operational on this. Can you help?"
the CM module does not continue with the network initialization if there is not another device that confirms its CAN messages
possible reasons:
- does the CM module run with the correct CAN baudrate ( see device parameters of the CM module in the hwardware configuration of TIA)
- does every slave run with the correct CAN baudrate ?
- is the mounting correct:
see chapter 4.4 Line Termination of the manual
- is the CAN bus correctly terminated ?
note:
the CAN bus has a line topology:
each end - but only the 2 ends - must be terminated with the correct resistor
- is the cable length to high ?
see chapter 4.3 Maximum Cable Lengths of the manual
- the configuration of the slaves fails:
first attempt:
Network Management Configuration in the Configuration Studio
Slave Assignment / NMT Slave: do not set bit 7
additional:
the customer shall install the update of the Configuration Studio:
- update of the Configuration Studio
close the Configuration Studio but do not uninstall it
run the unzipped update
open the Configuration Studio
