Reading Encoder data

[oktay.06]

Hi everyone,

I am using PXI and CompactRIO to build test systems. I wonder what is the best way to read the absolute encoder data, like Netzer VLG-60, on PXI systems. I investigate it and got some methods. I think the best option is FPGA. But i wonder any other relatively easy on application. I think counter modules like PXIe-6341, or PXIe-6612 might be implementable. I'm waiting for your suggestions in gladly. Thank You!

[ZYOng]

It depends on the encoder output signal (SSi or incremental), and how many units of encoder you want to read.

Netzer does not have VLG-60 model. Which model are you using?

[oktay.06]

Hi, there is a typo. I'm gonna use VLX-60 absolute rotary encoder that have resolution up to 22 bit, between 17-22 bit. Here is the page of this encoder:

https://netzerprecision.com/products/vlx-60/

Is the PXIe-6363 module can do this? Or what is the best way that easy to application?

Thank you

[ZYOng]

Since VLX-60 only supports BiSS-C or SSi but not incremental encoder.

Directly supported:

• Use FPGA Board to Implement Serial Synchronous Interface (SSI) with NI Products
• SEA 9521 BiSS-C/SSI Encoder Interface Module

NI-DAQmx devices including PXIe-6363 don't support SSI natively. If you really want to use DAQ, you need to tackle two challenges:

1. BiSS-C and SSi support only differential signal but DAQ only support single ended. You need to get a RS-422 to TTL converter.
2. Then you can use hardware timed digital input to capture the waveform. However, there isn't any decoding readily available so you need to develop it.

[oktay.06]

Thanks for your reccomendations. 

The link which I mentioned previous answer, is about VLX-60 technical informations. In Electrical Data chapter, they indicate that this encoder has RS-422 differential serial output. In this case, do i have to prefer FPGA-based solution, the combination is for example PXIe-7972R & NI 6584, or can i read data through this output with serial interface modules like PXIe-8431? Therefore, there is some converter modules that i can purchase with the encoder. I drop some screenshots about this. Thank you again.