Reference subtraction error in MathChannel ?

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plmohan
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Reference subtraction error in MathChannel ?

Post by plmohan »

I am trying to subtract a reference channel using the MathChannel operation:
B -B(2) . The result does not appear correct. In attached plot, the bottom Red trace is B, top red trace is B(2). The difference (MathChannel output) is the black trace. There appears to be a scaling error of some sorts. In this example, the 'live' B signal is unchanged from the stored Reference. If instead I set up for MathChannel = B+B(2) the resulting output looks correct and is simply a 2x doubling of input (B).
Tech support feedback welcomed.
Attachments
math ch Ref B(2).pdf
MathChannel Ref Channel subtraction
(478.55 KiB) Downloaded 63 times

bennog
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Re: Reference subtraction error in MathChannel ?

Post by bennog »

can you post a .psdata file

plmohan
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Re: Reference subtraction error in MathChannel ?

Post by plmohan »

Yes, .psdata file attached.
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20220913-0001.psdata
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bennog
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Re: Reference subtraction error in MathChannel ?

Post by bennog »

It has something to do with the name of the reference channel.
it was somehow interpreted as 2B so the result was B - (2 * B)
Renamed the reference to Bref and the formula to "B-{Bref}"
See the attached psdata file for the result

Then back to the original file and changed the formula to " B- {B (2)}" and it worked like expected.

Benno
Attachments
20220914-0001.psdata
(85.23 KiB) Downloaded 58 times

plmohan
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Re: Reference subtraction error in MathChannel ?

Post by plmohan »

Thanks for digging into this Benno. Working as expected now.
Cheers, Paul

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