Error -200077 at DAQmx Start when using map range custom scale

[tannerh13]

Hi All,

I'm working on a project where I will be creating a number of custom scales using the map range vi, and I keep getting this error code.  I have no idea where labview is getting the "Value Must Be Less Than: 662.65e-3".  From my understanding, the AI max and min properties should be in the scaled units, and I have those wired directly to the max and min in my map range vi, so I don't know where it is coming from.  Also, I am using an NI cDAQ-9179 with a NI9207 current input module.  That module should have an input range of +-20mA, so the 662.65e-3 doesn't seem to be referring to that limit.  I have included a vi replicating the error, as well as a picture of the error code.  Anyone have any idea what could be causing my problem?  I assume I might misunderstand how to use these vis if I am getting this error?

Thank you for any help.

[GerdW]

Hi tanner,

from the image you request a value of 60 where only a range of [0, 0.6] is allowed…

(Do you mind to downconvert your VI? Not everybody is using LV2020 yet, I do prefer LV2017.)

[tannerh13]

Hi GerdW,

Thanks for replying.  I'll look into down-converting the vi.  Once that is done and you can see the code, I think you might understand my confusion.

I see that the error message is saying that the maximum value I can put for the property is 0.6.  What I don't understand is where that value comes from. 

The daq equipment's range should be +-0.2 amp, and I am using the map range vi to map the 4-20mA output from my sensor into a 0-60 psi range. My understanding is that the min and max inputs to the analog input DAQmx vi should be in the scaled units (psi) when using a custom scale, meaning that 60 should be a valid input for the max value input.  (60 psi would correspond to 20 mA, which is within the hardware's range.)

But since I am getting an error, I must be mistaken somewhere in my reasoning, I just am not sure where.  If the max value input to the DAQmx read vi were actually intended to be in the pre-scaled units (amps) when using a custom scale, I would expect the error message to say that the max value for the property would be 0.2, but that is not the case, so I don't know what is going on.

In the mean time while I figure out the down-conversion, I'll include a picture of the code.

Thanks, I really appreciate the help.

Tanner

EDIT: I think I figured out how to save the vi in a previous version, and I've added it to this post.

[GerdW · Accepted solution]

Hi tannerh,

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@tannerh13 wrote:

The daq equipment's range should be +-0.2 amp, and I am using the map range vi to map the 4-20mA output from my sensor into a 0-60 psi range.

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Then why do you set the pre-scaled range to 0.04…0.2 (aka 40m…200m)?