2 probes differs

[oxd]

Hi,
I measure the same signal with the same probes but the signal differs in a vertical offset.
Is it correct to set the "Axis Scalling Offset" to "-0,30 %" on channel B to fix it for ever or is there another preferred way? It is normal that the channels differ?

[bennog]

if it is a 8 bit scope then 1/256 th is about 0.39 percent so then this is within limits.
but when you use resolution enhancement then this can be lower in theory.

but if it is a 2000 series scopen then the spec gives a 3% accuracy on DC values.

Benno

[Martyn]

Depending upon the scope model you have there may be an option to Zero offset each channel, check in the channel options menu or let us know the scope model.

[oxd]

The model is 2207B. Yes, that's in the 3% accuracy on DC values. I thought the channels should be somehow hw calibrated to be the same in the DC offset.

I can manually fix that by "Axis Scalling Offset" set to "-0,30 %" in the probe B settings. So is creating a custom probe with DC offset set and always using it the permanent fix to this or is there a hw trimmer inside or something like that?

[Martyn]

Use the Zero Channel Offset button in Channel Options window, which will do this automatically for all ranges, so you don't need to do this manually using a custom probe or scaling.

Remember this will need to be performed each time you use the scope as the offset may change due to environmental factors.