Problem with PMU data not showing/graphing consistently


After initial success, I’m having some issues with openHistorian 2.7.195.

I set up a fresh install yesterday, hoping to store data from two PMUs. Both of them were working fine for almost 20 hours and all was great, however without me altering the config one of the PMUs has disappeared. The PMU in question happens to be an ‘OpenPMU’ so I am able to get some diagnostics from the PMU side.

The behaviour I see is strange. I’ve listed what I see below:

  • OpenPMU data has stopped in Grafana. SG1 brand PMU is okay.
  • OpenPMU data and SG1 data both appear ‘live’ and good in openHistorian’s Real-Time Graph Measurements screen. Both PMUs have a green icon.
  • OpenPMU does not show a ‘Current Value’ on the Trend screen.
  • The database files grow at a rate indicating they do store values from OpenPMU. If I disable OpenPMU on the ‘Browse Devices’ screen, the database grows by about half the size as it does with both PMUs enabled. I’m using SQLite.
  • I can connect to OpenPMU with PMU Connection Tester (it works indefinitely like this).
  • According to OpenPMU’s diagnostics, openHistorian is requesting data and OpenPMU is sending it.

Some screenshots all taken within a few seconds (top left, Grafana no data for OpenPMU, bottom live data streaming okay, top right no live data for OpenPMU):

Any pointers and advice would be much appreciated.

Thanks for your help.

Check the clock time on the device giving your trouble.

Bingo! Somehow I was using an old version of the code which had a bug how it formatted time into C37.118.2. Updated to latest version, problem solved. It had confused me that I was still seeing the data stream in but it wasn’t presenting.

Thanks very much for your help and very quick reply! :slight_smile: