panelview 1000(2711-T10C1) No PLC Comm

[Drewster1123]

Last night electricians replaced the panelview and now there is no comms between the panelview and the PLC.

The processor is a 1747-L541 SLC 5/04 and has a 1747-SN scanner that connects to the HMI.

The Scanner is faulted out and has a flashing red fault led. The HMI has no comm or fault led's on.

Im not sure where to go from here.

I have a feeling that when the progam was downloaded onto the replacement HMI, the wrong address was assigned to the HMI which is causing issues. Im not sure though, I've never worked with these old HMI's.

Any help would be appreciated.

 

[AlfredoQuintero]

First let's cover the basic stuff. Did the electricians connect the termination resistors?
Did you set the baud rate of the PANELVIEW to the same value as the scanner?

 

[Drewster1123]

I was wondering about a terminating resistor. it doesn't look like there are any installed.
We just Tried changing the Baud rate around to see if it would make a difference but it did not.

Would the absence of a terminating resistor cause these issues?

 

[AlfredoQuintero]

Termination resistors are very important in DH+ and AB remote I/O networks. If there is none connected, I advice you to connect them at both ends, even if the previous setup did not have them.

 

[Ken Roach]

Did the terminal fail with a communication error, or did the screen go blank, or something else ? I'm hoping there is some evidence about whether the Scanner, the network wiring, or the terminal itself is faulty.

The 1747-SN has two indicator LEDs: COMM and FAULT.

The Installation Instructions say that a flashing red FAULT LED can mean three things:

Scanner configuration error.
No RIO link communication attempted.
Duplicate scanner detected on RIO link.

I presume that there isn't a rogue scanner attached to the network, and if the PLC is otherwise functional the configuration didn't change.

If the PanelView were the problem, then the 1747-SN FAULT indicator would be off, and the COMM indicator would be flashing green or red.

That suggests that the 1747-SN itself is the damaged component.

If the PanelView itself is functionaly, then it will display an error message during runtime that says "NO PLC COMMUNICATION". The COMM indicator LED on the back of the terminal being OFF is consistent with the 1747-SN not attempting to scan the network.