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Panel Shows All Question Marks on Screen (???)

Network connectivity issues between HMI panels and PLC devices will result in on-screen "?????" displays.

Applies to

  • PanelView HMI Screens

Kahler Automation uses PanelView human-machine interface (HMI) screens with 4000 series and 5000 series systems. These HMI units provide a customizable touch screen interface for operators, displaying system status and manual controls.

PanelView HMI screens require a network connection to a programmable logic controller (PLC) device to function. The PLC contains all system status information for the HMI to display; an inability to reach the PLC will result in all system details being replaced with question marks (“?????”) as shown below.

Troubleshooting

Troubleshoot PanelView showing all question marks:

Possible Cause

Solution

Power interruptions (brownout/blackout)
  • Power down the main control panel for at least 60 seconds before powering it back up. (This is the lowest-numbered control panel, often CP-100 or 101, located in the electrical room or office.)

Network interruptions
  • Verify that all network equipment is powered on and operational.

Network changes
  • Verify the PanelView screen and the main control panel have direct access to each other over the network.
  • Power cycle network equipment.
  • Check for correct operation of all network equipment.

Still Need Help?

Submit an online web ticket or call us at Kahler Automation 507-235-6648 Option 2.