I need help creating a threshold

Support questions about the Threshold plugin

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classen
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Posts: 115
Joined: Thu Nov 12, 2009 3:07 pm

I need help creating a threshold

#1 Post by classen » Mon Sep 09, 2019 3:01 pm

Hello

I have a script which polls a piece of vacuum equipment and retrieves 4 voltages. The voltages are then converted to pressure using the following CDEF RPN statement:

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cdef=CURRENT_DATA_SOURCE,11,-,10,LOG,*,EXP
The RRD file still contains the raw voltages, but the graph uses this CDEF function to convert the values to Torr.

I would like to create a threshold for these graphs so that if the pressure rises above 6.0e-8 or thereabouts it will trigger an email warning.

The instructions for THOLD specify that I must use the RAW data values for the thresholds, which I have done. I think this is working, but I would like the thresholds to appear on the graph at the converted values NOT the raw values.
Screen Shot 2019-09-09 at 12.56.00 PM.png
Screen Shot 2019-09-09 at 12.56.00 PM.png (116.76 KiB) Viewed 97 times
As you can see the threshold lines appear at 3.8/4.0 (the RAW values) instead of 6.3e-08 and 1.0e-07 (the Torr values)

netniV
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Posts: 2796
Joined: Sun Aug 27, 2017 12:05 am

Re: I need help creating a threshold

#2 Post by netniV » Wed Sep 11, 2019 4:34 am

This may be related to an open issue tracker on the thold github repo where CDEF's aren't being correctly applied.

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classen
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Posts: 115
Joined: Thu Nov 12, 2009 3:07 pm

Re: I need help creating a threshold

#3 Post by classen » Fri Sep 13, 2019 2:03 pm

Here is some additional information which may or may not help.

For reference here are the Volt (RAW) and Torr (derived from CDEF or RPN calculation) values for the thresholds:
thold_values.png
thold_values.png (271.05 KiB) Viewed 13 times

I have tried three of the Data Manipulation methods with varying results:

Exact Value - Threshold legend with RAW values appears on graph. Threshold vertical lines appear on graph at RAW values (instead of CDEF values which is what I want). Current Value in THold Status tab shows Raw value. triggers normally.
CDEF - Threshold legend with RAW values appears on graph. Threshold vertical lines appear on graph at RAW values (instead of CDEF values which is what I want). Current Value in THold Status tab shows Raw value. triggers normally.
RPN Notation - Threshold Legend is missing. No threshold vertical lines appear on graph. Current Value in THold Status tab shows the RPN derived value (i.e. Torr instead of Volts). Triggers false warning/Alerts.

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