Using cRIO-9024 serail port can I read the data from AFM60 absolute encoder, multiturn, SSI interface

Question

I would like to request you to kindly address the following quarries.
1. Using cRIO-9024 serial port, can I read or write data from AFM60 absolute encoder, multi-turn, SSI interface (please see the attachment for detail information about the encoder)?
2. Which type of encoder interface (SSI, TTL/HTL) is compatible with the serial port connection of cRIO-9024 controller?
3. Are there any limitation on choosing the output frequency and resolution (pulses per step) of the encoder? If the answer are yes, what are the suitable ranges of frequency and resolution?
Looking forward to your kind reply. Thanking you.
Regards
Shantanu
Attachments:
afs60_afm60_english.pdf ‏2298 KB

Answer 1

Hi Shantanu,
To read and write data from the serial port on a cRIO you access the serial port as a VISA resource, there are serial VISA VIs to read and write data on the serial port.
If you look under the Hardware Input and Output folder in the NI Example Finder, you should find a Serial folder, this contains examples for serial communication.
The serial interfaces on cRIO devices use the RS232 standard, unfortunately as SSI is based on the RS422 standard, you won't be able to directly interface the encoder to the serial port as they are not compatible. You would have to either use a separate interface between the devices or use a digital input module in your cRIO to directly process the encoder data.
To answer your question about frequency, the maximum baud rate for the serial port on the 9072 as listed here is 115200 bps, so this would be the maximum raw data transfer rate for any connected device, the number of steps for your particular encoder is limited by the maximum shaft speed as detailed in its specification. 
I hope this is helpful to you, feel free to ask further questions and I'll do my best to answer them.
Regards,
Adam Brown
Applications Engineer
National Instruments UK