Saving offset Null information - 9236

[PWoodward]

Hi all,

I am making an application with a cDAQ 9174 with a couple of 9236 modules in place. I want to be able to do an offset null when the strain gauges are in a neutral position however they probably will never go back to that neutral position again so I need to save that offset somewhere.

I tried to use the method stated in this KB: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019OSGSA2&l=en-AU

However this throws an error "-201398" "

Possible reason(s):

Requested value is not supported for this property. If you did not directly set this property to the unsupported value, check other properties that you have set, as they can influence the scaled value of this property.

Property: AI.Max
Requested Value: 1.0e-3
Value Must Be Greater Than: -105.245969e-3
Value Must Be Less Than: -25.586993e-6

Property: AI.Bridge.InitialVoltage
Corresponding Value: -97.062220e-3

Device: cDAQ3Mod2

Task Name: _unnamedTask<38>"

I'm not sure why the error says about requested values as I am asking it to give me the number that it has set for itself. I've tried with a for loop going through channel names (it wants tasks), I've tried changing active channels and get the same error as above (as per image) and I've tried single property call for the task (as per second image).

Ideally I want all the offset nulls that I can save to a file for each channel, then when the application is reloaded I want to then apply that offset to the new task.

I've been trying to avoid manually applying the offset but it is looking like that is the way to go unless anyone has any ideas in next couple of days.

Many thanks

Pete

[cbutcher]

Is it possible that somewhere between the values you're showing the Reads for, and the Write that is presumably throwing the error, you're changing something that effects the scaling of that value? Making the range of valid values change?

[PWoodward]

Unfortunately it’s the read that is erroring, I haven’t been able to get to writing yet.