EtherCAT Communication loss detection

[Akgaurihar]

Hello everyone,

Currently I am trying to find an answer for the following situation.

I have digital output and input cards connected to the Beckhoff CX PLC. In case of EtherCAT communication loss ( Let's say cable is damaged or disconnected by someone ) digital outputs goes to the zero state, but the inputs always remains to the TRUE state.

I want to detect the EtherCAT communication loss and using this want to safely reset digital inputs until the communication is up again. What is the best way to handle this situation. Looking for expert advice.

Thank you and have a nice day.

 

[LadderLogic]

The inputs reflect the state of the devices connected to them, they cannot be “reset”

 

[James Mcquade]

try this.

send an output signal to your device. connect it to an input
start a 1 second timer when you turn on the output.
look for that input to turn on. then turn off the output and start a 1 second timer. the input signal should turn off. this is a heart beat signal.

if either timer times out, something is wrong.
as far as the inputs goes, copy the inputs into memory words.
as long as the heart beat is working, copy the inputs into th words.
when the signal fails, turn off that rung and turn on a rung to copy 0's into the same registers.

i may not have this exactly correct, you may have to play with it. if someone else has a better way, please comment.

regards,
james

 

[parky]

#1 James heartbeat is the way to go unless there are built in diagnostics.

 

[JesperMP]

You cannot specify the behaviour of the inputs upon loss of connection ?
I would guess that like with Profinet you can specify the inputs to hold last state, or go on, or go off.

 

[Zensequitur]

Another option would be to use the Beckhoff's EtherCAT library. If there is an EtherCAT related fault, you can use these to diagnose and troubleshoot issues from PLC Code.

For TwinCAT 3
Tc2_EtherCAT

For TwinCAT 2
TcEtherCAT