Emerson Exchange 365

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Wireless Values Stop Updating

We have a Rosemount 1420 Wireless gateway commissioned in the last year.  We have had two instances where all our wireless instruments stopped updating and went to MODBAD status for about 8 minutes before starting to work again.  We cannot find anything that is causing this to happen.  Is there something we should be looking at?

Glenn Faber

• 4 Jan 2021 7:04 PM
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4 Replies

• John Rezabek

  

  • 6 Jan 2021 1:35 PM

  You would think - having commissioned this gateway in the last year - you would have a recent firmware release if not the latest. Maybe check where you're at and post it. The 8 minute outage sounds like a restart or a power cycle. But - depending on how many devices are connected and the complexity of the mesh - you'd think the devices would come back online more gradually. Is that what you see?
  Where's the power coming from? Is it redundant?
  Are you connected via the DeltaV PCN or are you using Modbus / something else?

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• Glenn Faber

  

  • 6 Jan 2021 6:46 PM

  In reply to John Rezabek:

  Firmware is 12.7.61. Final Assembly #7768. Power is redundant. We are connected via DeltaV PCN. We found a log file from the web interface that says the gateway had been up for 450 days (so we have had it in for a little over a year) and shows no reboots since commissioning.

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• mco_exchg

  

  • 6 Jan 2021 8:16 PM

  My 2 cents:
  
  1) If your gateway has the coaxial remote antenna, check the joint connectors between the gateway, the cable, the lightening arrester and the antenna, are they tight? do they look damaged/corroded or are they properly insulated? Also, I've seen intermittent faulty antenna cables, probably bent too much during installation, that seem to be fine externally, but after replacing with a new one for a test it turned out to be a faulty antenna cable, the behavior was similar, no reboots in the logs but lost of all devices, then all would recover eventually.
  
  2) Is there new 2.4GHz traffic near the gateway's antenna? I have also seen the same no reboots/intermittent loss of devices/network recovers, turned out the site's business IT team had installed a WiFi Access point for business use (heavy traffic) 6-8meters from the HART Wireless Gateway causing heavy interference with the WiHART signals.
  
  Interesting to see what your issue turns out to be. Good luck !

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• John Rezabek

  

  • 8 Jan 2021 6:34 PM

  In reply to Glenn Faber:

  The fact that all the connected devices go from NaN -> okay more-or-less at once (right?) makes me think you're seeing an issues with DeltaV connection to the Gateway versus a wireless issue. But maybe the intermittent bandwidth intrusion described by @mco_exchg looks similar, i.e. the mesh doesn't need to "rebuild" just because a box truck parked in front of it.
  Is there any fiber / media converter or other intervening switch / firewall / router between the DeltaV switches and the gateway? Are any such appliances "shared" in some way by both primary & secondary PCN?

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