Wiring a NI 9237 and a Torque Transducer

[T.Tsuzaki]

Dear All

Newbie to these forums and NI equipment in general

I have a NI 9237 and using Labview 2014. I have recently managed to connect a couple of load cells to the NI 9237 and the VI I built for it is working great!

I now have to use a torque transducer and wondering whether the NI 9237 is suitable for my particular piece of equipment?

I have attached the data sheet for reference, and the transducer I have is the RT2A 5NM. There are a couple of areas that concern me on the data sheet are: (and please be gentl if these are simple assumptions or misassumptions I am making).

1) The nominal output is +/- 10V

2) The Nominal Power supply suggested is 15-24V (Can the NI9237 supply such Excitation voltage?)

3) The electrical wiring connection seems to rely on the supply voltage connection for the output voltage? (is this safe for the NI9237)

For point 1 in particular I cannot seem to find any calibration for scaling? or are torque transducers generally considered linear relationship between highest voltage and highest torque measurement possible?

Sorry if these all seem quite basic questions, the 9237 was quite expensive module so don't really want to rely on trial and error to build my next code?

Thank you for reading this post!

[jinfone.t]

Hi T.Tsuzaki,

When you say you assume that the nominal output is +/- 10V, are you talking about the module?

The NI 9237 can supply excitation voltages of 2.5, 3.3, 5 or 10V as stated in the Operating Instructions and Specifications, page 16.

[T.Tsuzaki]

Hi there

Thanks for your reply, no the actual torque sensor is pre-amplified so already outputs a signal voltage of +/- 10V.

I can supply a excitation voltage seperately. From the spec sheet it states the ex. voltage should be between 15 and 24V which I believe is more than what the 9237 can put out.

Regards

[T.Tsuzaki · Accepted solution]

Hi everybody

Just to let you know.

Spoke to the manufacturer. it is fairly standard that if a transducer unit is already amplified and producing a reasonable voltage output such as + or - 10V. Then the requirements are that you will ony need a scalable DAQ to change the voltage into torque readings.

In my case the torque meter was calibrated at the factory to read upto 5NM and therefore the maximum output voltage of 10V will be the equivalant of 5NM. The voltage/torque relationship is normally linear. So for every volt should be the equivalent of 0.5NM. The manufacturer calbration shows that the normalised voltage at rest is approx. 0.001V.

The excitation voltage is relevant as there is a amplifier built into the transducer therefore the supplier is somewhat higher at 15-24V rather than the normal 2.5-10V that non-amplified transducers require. The NI9237 cannot supply the higher voltage therefore a seperate voltage will need to be applied. The range in excitation voltage is only relevant when certain factors such as cable length and amount of interference become apparent. As a rule of thumb use as little excitation voltage as possible is the best The actual excitation voltage used by the transducer is normally regulated internally so whether supplying 15 or 24V will not have much of an impact (unless you are suffering from the aforementioned conditions).

Hope that helps