sensor connection to NI 9219

[swdu]

I am going to connect a displacement sensor to NI 9219, the sensor has one ground, one input 6-16V DC, one output 0-5V DC, appreciate if anyone can tell me how to connet properly.

[mallorim]

Hi swdu,

Welcome to the forums! The 9219 is a Universal Analog Input. Since your sensor returns voltages, you will want to operate in Voltage mode. In this mode, pin 4 on one of the terminal connectors is the signal input HI and pin 5 is the signal input LO. You will therefore most likely want to connect your sensor’s output to pin 4 and the ground to pin 5.

The 9219 has no outputs to wire to your sensor’s input. If your sensor needs excitation or power to be wired to this terminal, you will need some form of external excitation or power source or else a card with an analog output capable of reaching the 6-16V you mentioned in your post. You will also need to watch the level of current the sensor will draw and be sure that any voltage source you use will be capable of meeting those current requirements.

Hope this helps, Mallori M.

[swdu]

Thanks for your reply.

[ckboiler]

I see what you are saying, but in Labview 2010, you now have Custom voltage with Excitation?  Could you power the sensor in this way?  I need only 5 V, but could use 2.5 V for my purposes, which I believe is the max that the USB-9162 can supply to the NI9219?  I have a very similar rotary position sensor that I want to power and just see the Output of the linear ramp.  Sensor has a Ground Wire/Power In/Analog Out.  Thanks,

Thanks,

Chris

[The_Red_Barron]

Howdy Chris!

The NI 9219 is capable of providing 2.5V of excitation so it should work for your application with the rotatory position sensor with the USB-9162.

Regards,

[ckboiler]

Thanks, that being said:

If Pin 4 is Signal Out, Pin 5 Is Ground, which pin should be the power supply?  Would I then want to set up a Half Bridge to power my sensor with the Power coming from Pin 3? 

If the Sensor then would be registering a 0-2.5V output, based on a reduced input, do I then need to adjust the Signal Input Range or enter a custom scaling?  It appears that it is setup to only take or allow -25mv to 25mV input back in from the sensor, which doesn't seem right.

Thanks for the help,

[dousley]

Hi Ckauf,

Yes, you would want to configure this as a half bridge. Just as you described.

When using the 9219 in half bridge mode, the module's range is actually +/-500mV/V. "+500mV" would indicate that the sensor is twisted to the point that all the resistance is in the lower leg and none is in the upper leg. "-500mV" would indicate that all resistance is in the upper leg, and none in the lower leg. "0mV" would indicate balanced legs.

And to address a comment you made earlier about using the 9219 with a 9162 single slot USB carrier, the 9219 will have the same current sourcing abilities in a 9162 carrier as in any other carrier.

Hope this helps,

Daniel