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comparing 2 channels using Sensor Factory




How do i compare the values of two (or more) channels in the Sensor Factory and alert if they return different numbers.


I have a checksum that runs on a database table, it returns a number, this checksum runs on what should be identical copies of this database.

so i have Channel Definition


and i want to go into error state when channel(5087,2) <> channel(5088,2)

I tried

Status Definition

(channel(5087,2) - channel(5088,2)) = 0


Status Definition

(channel(5087,2) <> channel(5088,2))


Status Definition

(channel(5087,2) != channel(5088,2))

and none of them went into error state when the channels reported differnt values. How can this be done? Also, can i compare 4 channel values and go into error state if any of the values differ from the others?



channel compare prtg sensor-factory

Created on Jun 5, 2012 10:34:42 PM

Last change on Jun 6, 2012 11:35:10 AM by  Torsten Lindner [Paessler Support]

4 Replies




the Status-Definition field can only handle expressions with the STATUS(...)-command, not the normal channel-definition formulas.

best regards.

Created on Jun 6, 2012 11:37:41 AM by  Torsten Lindner [Paessler Support]



Can you provide more details beyond "what you are doing is wrong" to help me solve my problem?

Created on Jun 6, 2012 2:38:19 PM



Okay, you cannot use the Status-Definition field for such calculations. So, why not creating a 3rd channel with

(channel(5087,2) - channel(5088,2))

and then setting Error-Limits on this channel so that everything below and above 0 sets the sensor into an Error state?

Created on Jun 6, 2012 2:47:07 PM by  Torsten Lindner [Paessler Support]



Thanks, that was helpful.

For documentation purposes:

I wanted to make sure a (small) mysql database table was being replicated properly, so i created a MySQL sensor on each database that did a query like this:

select SUM(name + content) from records

this returns a number that is used in a Sensor Factory channel definition where i compare the two values by subtracting.

The sensor numbers are 5099 and 5096 and the channels (as listed under mysql channels tab 'Value ID') were both 2.

  1. 1:Table1vsTable4 (channel(5099,2) - channel(5096,2))

This value should always be 0, so setting the sensor factory sensor to alert when channel Table1vsTable4 was greater or less than 0 worked great.

Created on Jun 6, 2012 9:24:41 PM

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