PLC 5/30 Comm Problems!

We have had a bad problem with this error for quite a long time. Here is what our print says.
Channel B
PLC 5/30 -> PV1000 ->1747-ASB ->1791-24AB (150ohm resistor)
Channel B
PLC 5/30 ->1791-24AB ->1747-ASB ->1791-16AC (150ohm resistor)

Channel A
PLC 5/30 -> KF-2 Datalink ->Console -> Console -> Panelview 1000

The only thing different from the print to the machine, is that there is also a resistor in each channel at the PLC5.

We have ran new cable, checked all dip settings, and checked all connections. The problem comes and goes, some days worse than others and some days its non existant. We have also put an o-scope on the comm cable from drain wire to plc chassis, and the results were interesting. Channel A, had 157mV AC, and Channel B had ~1mV AC. Would that be a noise issue? If so, where do we begin? What do we check for?

If anything else looks odd, or you need more info, I have access to the PLC5 and its parameters. Thank you for your time.

I forgot to post the actual problem. lol
Error 665 on the PV 1000.

Welcome to the Forum!

A couple of questions. Channel B is set up RIO, and Channel A is set up as DH+.

Is that correct?

What is the Baud Rate on both Channels?

On Channel B, the PLC is in the middle of the chain?

The AB DH+ and RIO are very dependable, but must be wired with the correct Blue Hose, and terminated with the correct Resistors for the Data Rate at each end of the Network. The Shields must be neat and preferably insulated with Shrink Tubing or similar method at each connection point. Avoid Power Conductors as much as possible, and if they must cross paths, try to cross them as close to ninety degrees as possible.

Stu....

Thank you for the quick reply Stu.
A - DH+ 57.6k (it is grayed out and cannot change it)
B - Remote IO Scanner 230.4k

Yes the PLC 5 is in the middle of the chain. The drain wires are not heatshrinked and I know of one junction box where the blue hose runs through that has other wires in the box, but not ran through the same conduit. Any other info needed I can gladly get. Thank you.

Is the PanelView the only item experiencing Communications problems?
What is the exact Model Number of the PanleView?

150 Ohm Resistors are for 57.6 KB
82 Ohm Resistors should be on the 230.4 KB, so these should be changed on the RIO Network.

Error Code 665 Means that there were Communications, but the PanelView is no longer receiving BTW/BTR Requests from the PLC.

It is possible this is a PLC Programming issue if the PanelView is the only item experiencing problems. Have a look at the BTW/BTR Instructions in your PLC Code associated with the PanelView.

Stu.....

Thanks again Stu. Thats interesting about the resistors. I will have to dig deeper on that issue.
The PV # is 2711-T10C1X Ser. D Rev. D Frm. 4.41

When this 665 error occurs, all of the machines shut down. Even the other panel view at the other end of channel A says it cannot connect to specified node. If power is recycled on the PLC 5/30, the comms will come back on and will function normally. I have also tried having a laptop hooked to it directly to see of maybe I can get some kind of fault and when the error occurs, it also drops the comms to the laptop.

Thanks again.

PS. I have not dealt with BTW/BTR code that goes with a panelview, only analog cards and thermocouple cards. Could you explain a little more on that please?

Ok, this sounds like a deeper issue.

Is the PLC still in Run Mode when this happens?

What are Communications LEDs on the PLC doing when Commuications fails?

i.e. Solid Red, Flashing Green etc.

Stu....

The PLC is in Remote, and the comm lights go off. Only light on the processor is the Processor light and it is a steady red.

seth350 said:

The PLC is in Remote, and the comm lights go off. Only light on the processor is the Processor light and it is a steady red.

Click to expand...

It sounds like the PLC is shutting down completely. Here is the AB Manual for the PLC5, have a look at Appendix F regarding the Status LEDs.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1785-um012_-en-p.pdf

Stu....

Ok, I know of one time back before we had all these problems that there was not a battery at all in the processor. It faulted one night and we had to reload the program. Since then a battery has been installed, but I have not checked it. Even still, if I cycle power when I get this error the program is still on the processor. So no memory loss that I can think of.
I will add, that while I had a laptop plugged up to it. I got a red FAULT COMM. in Logix5. I will also add that there are some other warnings on the processor. "DH+ Data Table Changed", "Arithmetic Overflow", and "IO Update" or something along those lines.

And I will add that it will sometimes correct itself and not require a power cycle...

Can you post your RSlogix5 RSP File? (Zip it first, Forum Rule)

Stu....

This doesn't appear to be a working program. There are no JSR Instructions to the Subroutines, Scan Time is zero, and it has no saved Faults. Not to mention a bunch of other Parameters that are zero or incorrect.

Stu....

That is the program on the PLC 5/30.
Whether or not the JSRs are somehow controlled in any of the other SLCs on the chain, Im not sure. We dont have them linked into the network and I have no immediate acces to a laptop right now.
Wouldnt the PLC just scan through them regardless? And the machine has been running all night and for a long time with that program, unless I somehow didnt save it right or export the right data.

Here is another file, I just saved it from the PLC5.

seth350 said:

That is the program on the PLC 5/30.
Whether or not the JSRs are somehow controlled in any of the other SLCs on the chain, Im not sure. We dont have them linked into the network and I have no immediate acces to a laptop right now.
Wouldnt the PLC just scan through them regardless? And the machine has been running all night and for a long time with that program, unless I somehow didnt save it right or export the right data.

Here is another file, I just saved it from the PLC5.

Click to expand...

That looks better, the Subroutines are called in the MCP, and they have Scan Times. As well there are valid values in the Parameters that were zero or invalid in the first program you posted.

Stu....