Anybus AB7306, Can Not Responding

Hi, Is there any known issue with the device AB7306 and the canopen network not working or locking up. It happens only sometimes.
I have drives on the canpoen network that turn off and on. When turning on the drives, sometimes the canopen locks up in the anybus. No error is shown by the anybus. Also, I can communicate through ethernet with the PLC, but no matter what value I put in the PLC, nothing comes out to the drives from the anybus on the canopen side.
Only solution when this happens is to power cycle the anybus and everything works back again.


I am not aware of any current issues with canopen locking up. Looking at the change logs for the last firmware, released in 2016, one of the bug fixes was related when a slave was powered off but not reconnecting when booted back up.

Problem getting the slave node online after a disconnection of the cable (master does not react to
slave boot up msg) – The master and the slave could get stuck in an eternal loop with the master
reseting the slave when it received the bootup message. Now the reset is removed when the slave’s
bootup message is received and it starts polling the 0x1000 object instead. This is a complete restart
of the error handling of the slave. Internal ID: 0007131.

You might want to check the firmware on your device and update if you have an older firmware version. The firmware is available on the files and documents page on

You might also be able to use the control word to make sure the device and bus are in run mode. The node might just need to be set back into run.


Deryck, the thing is that the anybus doesn’t respond at all, so I can’t check what is happening in the network. I thought I was using the last firmware but I see there is a new one so I’ll try that and let you know.

Thanks and regards,


Hi @grolon,

If the firmware update does not resolve this issue here are a few things to check.
Make sure you have 120Ohm resistors on both ends of the bus with 60Ohms measured across the high and low sides.

You can also use the USB-to-CAN to check the bus for communications. Using the log feature you can check if the Master is sending any messages.