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Voltage and Current Meassurement Card for cRIO

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Hello NI Community,

 

My Bachelors thesis requires me to modify the system of our calibration robot. At the moment we are using a cRIO for driving our calibration robot an recording the measurement values. Those measurement values were transmitted as voltage signal, but we want to replace our measurement amplifier with an new one, which is configurable to both output voltage or current. The new measurement amplifier can be configured using 2 digital lines and outputs the current configuration using the measurement output with an voltage signal. If current is selected as signal for the measurement values, the configuration is still done using voltage. This requires us to use a measuring card for our cRio which is able to take current and voltage at the same port, ideally at the same time.

 

Does National Instruments offer cards, which are able to read both voltage and current? Like the NI 9207 but with the possibility to measure both at a single port.

 

I hope you can help me and NI offers a suiting card.

 

Best regards and thanks in advance,

 

Solembum

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Hi Solembum,

 

NI 9207 has 8 current and 8 voltage inputs and I think for your application this is as good as it gets. This would allow you to perform both current and voltage measurements using the same module but not the same port.

 

Actually, in order to measure current you need 1 port and for differential voltage measurement another 2 ports, if the module supports differential voltage measurement. Moreover you cannot use the current port as one of your voltage port(s).

 

If you want to perform synchronous acquisitions, then you can achieve this programmatically using LabVIEW.

 

Hope this helps,

Bart

 

 

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Hello Bart,

 

thanks for your help. Having to use two separate ports for input is quite impracticable. I need the possibility of using the same port for current and voltage measuring but not at the same time. During configuration I need to measure voltage and during calibration i need to measure current.

Further searching brought me to the NI 9219 which seems to satisfy those requirements. But i could not find further documentation how to use the NI 9219 with LabVIEW.

 

Best regards,

 

Solembum

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Accepted by topic author Solembum
05-31-2017 11:13 PM

Assuming a 4-20mA signal, you could just add a 500 Ohm resistor in parallel with your voltage channel during calibration.  20mA*500 Ohms = 10V.


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Accepted by topic author Solembum
05-31-2017 11:13 PM

Hi Solembum,

 

To program NI 9219 the most critical thing is to configure the modes and ranges of the module. The following link should help you with that:

 

Configuring Modes and Ranges for the NI 9212

http://zone.ni.com/reference/en-XX/help/370984R-01/criodevicehelp/9219_setting_modes_ranges/

 

Also there is a sample project under "labview\examples\CompactRIO\Module Specific\NI 9219\NI 9219 Getting Started\NI 9219 Getting Started.lvproj". You can easily start with that Smiley Wink

 

BR,

Bart

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Hi crossrulz,

 

Thank you for your hint, I will take this into account. If should later need unexpectedly to measure voltage and current at the same time, I guess thats the only option.

 

Best regards,

 

Solembum

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Hi Bart,

 

Thank you for the Link. I did not find that one. It looks like it's what I was searching for. I will try and tell the outcome.

 

Best regards,

 

Solembum

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