Does anyone know how to start the modbus client from the run screen of the UR?  When you are in the program screen you can go to installation and then modbus client and hit the "refresh" icon up in the upper right corner.  When our customers are in the run screen though there is no way to perform this task when we first turn on the robot.  Is there a way from script to execute the same functionality that we can just add to the top of the program?

@Stefan_Stubgaard any suggestions?

@matthewd92 no script for "refreshing the client" is available. What happens when you press the "refresh" button is that all modbus signals are deleted and then added again by using the standard script codes modbus_delete_signal() and modbus_add_signal()

So @Stefan_Stubgaard what do we do when we first turn on the robot from being powered off to get modbus back up and running?  Do I have to basically give the customer the password to go to the program screen so they can refresh?  On power up the modbus is not active and if you hit play the program just faults out. 

Under normal circumstances the modbus client should automatically start up when the robot is being powered up and installation file is loaded.
If this fails there might be an issue with the amount of assigned signals, amount of devices or the specific device you are trying to connect to. This can be reported using your normal communication channel for our R&D to investigate.

I have also been having this problem. I am using two register inputs and one register output. I had to give my customer the password to refresh this. has anyone figured out a better solution to this problem? 

@roehlkk If you just press play, it actually does the refresh for you.  Sometimes you need to press play a couple of times.  Also, we tied in the e-stop button into the modbus power supply so that by simply pressing the e-stop, we turn off the modbus and then turn it back on.

From the best I can tell the issue is the watchdog on the modbus server.  The unit that we were having the most trouble with I was able through the configuration software to go in and turn off the watchdog timer.  This seems to have basically eliminated the problem but still have the occasional issue but now we just tell the customer to press play a couple of times, if that does not clear it up then hit the e-stop.

What kind of device are you using, we have the most issue with the Automation Direct modbus client, its like a Beckhoff so the instructions for the Beckhoff from the UR website also helped.  We have switched to a Turk system on our newer robots and we don't seem to have the issues that we used to have.

Thank you @matthewd92, I will have my customer try hitting play a few times and tie into the e-stop next time I go in. I am using a B&R X20 system with a Modbus bus coupler. 

What software version are you using?
There were some improvements to modbus client in version 3.4.3.

@mmi good point. I had forgotten about that. I can say that things definitely got better after that release. 

@mmi, I am using software version 3.4.3. Pressing The play button a few times seems to work well for my customer.  

@roehlkk is the error that a signal is disconnected?  We still see that occasionally as well and the play thing resolves it well. Just annoying.