cRIO support hardware module for LVDT input

[Gearmiester]

While I realize that there is already a third party option for this, it only makes sense that NI open an option for the cRIO users out there that can do what this module does...

https://www.ni.com/en-us/support/model.scxi-1540.html

in a cRIO platform module. That way we can have a North Anmerica source for this very important data input device.

Optimally two - four channel input on a single module design.

[Dan_Alias]

Yes I agree. Further, not just cRIO but cDAQ. Not just LVDT, but Synchro/Resolver.  Not just input, but output (to simulate a Synchro Transmitter in order to drive a Synchro Receiver). So perhaps a full product offering in cDAQ/cRIO form factor for variable differential transformer (VDT) devices.  Like Bloomy's 8-channel SLSC but fewer channels, maybe even only 1 per module if necessary, and maybe even only in or out per module.  It seems like most NI customers only do angular/linear position measurements (inputs) but in the flight simulator world, we do a lot of angular outputs like in aircraft.  Aviation testing probably needs both styles as well.  See UEI's DNR-AI-255 Synchro/Resolver 2 channel input & output module.  It seems like NI has been on the cusp of supporting these kinds of devices for decades, but never has jumped all in and done it right.

[User002]

So NI has the PXIe-4340 now, which was intended as a replacement: https://www.ni.com/en-us/shop/model/pxie-4340.html It acquires LVDT, RVDT, or resolver signals.   In my opinion, it misses the mark.

First, it has a delta-sigma based architecture.  Those have long pipeline delays.  Often these kinds of sensors are used single point style, in control loops, and the latency of that architecture prohibits use in that way.  Really it eliminates one of three use cases I see.  Outside of control, there are lab systems (which have sole ownership of the sensor) and there is passive datalogging (where another controller is using the sensor to close the loop, and the NI-based system is logging.

For passive datalogging, sadly , the 4340 cannot use an external reference for excitation - which is what it would likely have to do in that case.  Typically the controller in place already provides excitation.

I hope that NI doesn't see poor sales of that modules as a lack of need.  Rather, I see the PXIe-4340 as a poor solution for that space.

In my opinion, the right solution includes:

- a SAR-based (not delta-sigma-based) architecture with low latency (so control is viable)

- It can accept an external source for excitation (so passive datalogging is viable)

- A companion cRIO module with smaller channel count (for smaller or embedded systems)

I see a strong market need here - if those features can be delivered.

In the meanwhile, I see a c-series modules from SET that does this: https://www.smart-e-tech.de/en/products/rdk-9316-resolver-demodulator/