Line 4 filler here, PanelView Plus 7 Performance 12 inch, application built in View Studio ME V12. It logs 14 tags, temperatures and the fill weight, to a data log model on the SD card, one sample a second. The trend showed history fine for about three weeks after the terminal was replaced, then it stops dead on the 12th and is empty from there. Live values on the same screen still update, so the comms are up.
I power cycled the terminal twice, no change, then pulled the SD card and looked at it on a laptop, where the log folder has files in it dated the 12th. No alarm, no error on the terminal, nothing in the diagnostics list.
Is the trend object broken or is it the card? QA want the weight history and I'm stuck. Is there a size limit on a data log model that would just stop it dead on the 12th and never say a word?
How big is the card and how full is it? And what's the model's maximum data points set to, Data Log Models, Setup tab. One a second on 14 tags fills anything in weeks. I reckon that rate got set for a tuning job once and never put back.
Card is 2 GB, the laptop says 3 MB free. So it's full. Max data points on the model says 300000. There's a second model on the same card for the alarm history, and someone had the terminal saving screenshots to it as well.
3 MB free explains all of it. The datalog doesn't warn when the path fills, it stops writing and the trend ends on the last sample. Live values keep going on the same screen, so nobody notices for a week.
What changed since it last worked is the card, the old terminal had a bigger one. Data Log Models, the model, Setup tab, drop the rate from 1000ms to 5000ms unless QA really wants a sample every second on a 4 s fill. Then the Paths tab, put the datalog somewhere of its own and leave the alarm history where it is. Delete the screenshot folder. Create Runtime again and load it, the model is baked into the MER.
There's a writeup on the logging side of this here: https://plctr.com/best-practices-for-plc-data-logging-and-remote-monitoring/
Cleared the screenshots and the old alarm files, 900 MB free, restarted the PVP7. Trend started moving again from today, but the pens are blank between the 12th and now. Is that gone for good?
Gone. Nothing logged, nothing to show. The files on the card dated the 12th are the last good ones, copy them off for QA before the model overwrites them.
Moved the datalog to a new 32 GB card, rate down to 5000ms, rebuilt the MER in V12 and loaded it last night. Alarm history stays on the old card. Trend's been running two shifts now and the card is barely touched.
Turns out the card was simply full. 14 tags at one a second, plus the alarm history, plus a screenshot folder nobody here knew about. The datalog stops when the path fills and says nothing anywhere, which is the part that got us. More space and a slower rate and it runs.
Not sure whether the 300000 max data points is per tag or across the whole model, the dialog doesn't say. Left it alone.
Thanks priya87, and louk for asking about the free space first.
A screenshot folder nobody knew about. Of course there was.