PV Plus 700 - intermittent no comms after boot

BAJ · Oct 13, 2017

I have a customer who has a machine with 2 PVP 700's on Ethernet/IP to a CLx L72 processor. It's a machine that is powered-off every night. Infrequently, they will power up the machine in the morning and one of the two PVP 700's will not communicate to the PLC (same one every time). If they cycle power again, it works.

Any thoughts on a cause for this? I haven't poked around much in the PV OS, is there a local event or error log on the PV that would might capture some info (h/w or driver issue?) that would point to a source of the problem?

Thanks,
-Brad

jstolaruk · Oct 13, 2017

I've noticed that Panelviews boot faster than the newer processors and fault when the comms can't find the processor because its still booting. I'm betting that if the PV in question was rebooted by itself while the processor remains on, it would boot just fine.

As far as what to do, can the processor be left running while the other power hungry components be turned off? If not, how about a normally closed push button in series with the power connection to the PV? Then just the PV is rebooted instead of the entire machine.

dmroeder · Oct 13, 2017

We've seen this when using Stratix 5700's. It seems that the boot up time is pretty similar between the Stratix and PanelView, if the switch wasn't ready by the time the PanelView was ready, it wouldn't talk. Turned out if we just navigated to a different screen on the PanelView, it would start communicating within a few seconds.

We temporarily put in a switch that booted faster and it would never happen. I found tech not 675867 that discusses what sounds similar. The suggestion is to power the switch separately, or plug the PanelView directly into the PLC.

janner_10 · Oct 14, 2017

Power the PVs through a relay. Get the PLC to turn on this relay.

BAJ · Oct 14, 2017

Thanks for the replies.

The machine is in a hazardous environment and when they turn off purge blower off at night, it all gets powered down, no power to keep anything up.

We have an N-tron switch, which is very fast to power on. The L72 boots faster than the PV's. Also, both PV's come up at the same time, so why one would intermittently fail on comms and not the other doesn't seem like a timing thing.

I was pointed to a tech note on a different issue which said the Ethernet/IP driver had a glitch requiring a f/w upgrade, so I'm going to try to upgrade the firmware and see if that helps.

Otherwise we might be installing a selector switch on the power going to the one glitchy PV.

janner_10 · Oct 14, 2017

BAJ said:
Thanks for the replies.

The machine is in a hazardous environment and when they turn off purge blower off at night, it all gets powered down, no power to keep anything up.

We have an N-tron switch, which is very fast to power on. The L72 boots faster than the PV's. Also, both PV's come up at the same time, so why one would intermittently fail on comms and not the other doesn't seem like a timing thing.

I was pointed to a tech note on a different issue which said the Ethernet/IP driver had a glitch requiring a f/w upgrade, so I'm going to try to upgrade the firmware and see if that helps.

Otherwise we might be installing a selector switch on the power going to the one glitchy PV.

KISS. Do the above.

James Mcquade · Oct 14, 2017

BAJ,

You said the magic words, "hazardous environment"
since the machine is turned off every night and the purge blower is off also,
I have some questions.

Since the area will get powder all over it if you turn off the purge blower, is this a class 2 div 1 area?

if yes, how is the inside of the control panel protected from dust?
purging or pressurization?

where are the pv terminals and how are they protected?
please look for the class ratings on the terminals.

in regards to communications, do the terminals have the same ip address?
we had that issue 2 years ago, an old system was pulled out of mothballs and turned on.

regards,
james

BAJ · Oct 15, 2017

Thanks for the reply James.

The hazardous rating is for solvents, not powder. Small amounts for short periods of time. It's one of those situations where it was installed to meet the letter of the law, and perhaps would be more necessary if they used it differently, but is almost certainly over-kill for what it is currently doing.

The machine is very clean, inside and out. And each PV has a unique IP, I've downloaded updates to both over the network. In fact, there is a dedicated 1756-EN2T just for the two PV's.

PV Plus 700 - intermittent no comms after boot

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