This article is for robots running PolyScope X. If your robot runs PolyScope 5, see Troubleshooting Fieldbus Communication Loss with Miller Auto Deltaweld 350 (PolyScope 5).
The Miller Auto Deltaweld 350 power source talks to the robot over a Modbus connection. When that connection drops, your weld program stops and the teach pendant shows a Modbus signal error. This article will help you fix it.
What You'll See
Main program: An error occurred in the running programon the teach pendantMODBUS Signal weldFeedback_digitalin the error detailsThe weld program stops
Quick Fix
Restart the power source. This often brings the connection back.
If That Didn't Work
Check the Power Source's Ethernet Cable
Check that the Ethernet cable is plugged in firmly at the power source and at the port on the robot's cabinet. The power source comes with a screw-in Ethernet cable. Line up the pins, then screw the cable into place.
Check the Robot's USB-to-Ethernet Adapter
Inside the robot's cabinet, a USB-to-Ethernet adapter connects the cabinet's outside Ethernet port to the robot controller. Check that the Ethernet cable is plugged in firmly at the adapter. Check that the adapter is plugged in firmly at the robot controller.
The adapter's light should be solid or blinking. If the light is off, unplug the adapter from the USB port, then plug it back in.
Check that the Modbus TCP Server is On
Your robot uses Modbus TCP to talk to the power source. It does not use Ethernet/IP Adapter or Profinet Device, so leave them off.
On the teach pendant, open the menu, then tap Settings.
Under the Security section, tap Services, then tap Unlock.
Enter the admin password (default
beaconbot), then tap Confirm. The toggles on the Services list become active.
Turn on Modbus TCP Server. Turn off Ethernet/IP Adapter and Profinet Device. Then tap Lock and Close.
Restart the robot so the change takes effect.
Rebuild the Modbus Source
Deleting the source and setting it up again is faster than checking each setting one by one. Follow every step, even if some of the settings already look correct.
On the teach pendant, tap Application twice to go back to the app list, then tap Communication.
Remove every source listed under Modbus. Tap the three-dot menu next to a source, then tap Delete.
Under Modbus, tap Add Source.
Tap IP address.
Enter
172.18.181.151, then tap Confirm.
Tap Add Signal.
Under Address, tap From.
Enter
1, then tap Confirm.
Tap Add. The signal appears as Read Digital Inputs / MODBUS.
Look at Connection status. It should read Connected. If it still reads Not connected, restart the power source.
Still Need Help?
Tap the Support menu in Beacon to send us a message. It helps if you can share:
A photo of any error messages on the teach pendant or equipment
Your robot's serial number (printed on a label on the robot's base)
A photo of the Modbus: Source screen, showing the IP address and connection status