12-02-2011 09:02 AM - edited 12-02-2011 09:03 AM
I need an example for reading an SSI (synchronous serial interface) encoder value with a USB-6341 and labview 8.5.
12-05-2011 01:50 PM
What is your application? We are going to need a little bit more information.
Regards,
Alexander M
National Instruments
12-05-2011 02:08 PM
12-05-2011 05:48 PM
Thanks for the details, the links below should get you started.
Connect an absolute SSI encoder to a DAQ card
Reading SSI absolute encoder with USB-6008 DAQ
At this time it doesn't look like anything official from NI exists. However, it has been noted as a product suggestion in both the hardware & software realm.
Regards,
Alexander M
National Instruments
12-05-2011 07:35 PM
12-06-2011 08:30 AM
It looks like SSI code implementation in LabVIEW is mostly done on FPGAs, which would explain why timing in windows would present an issue.
LV FPGA SSI (Synchronous Serial Interface) Protocol
Regards,
Alexander M
National Instruments
12-06-2011 08:44 AM
12-06-2011 05:16 PM
Bkaspar,
Without having a data sheet for a particular SSI Encoder to look at, it seems like this should be possible with your USB-6341. However, I think it you'll need to use a combination of counter output and digital input to do what you want. What sensor are you trying to interface with?
In general, it seems like a procedure like the following would work:
1) Create a counter output task with the following settings:
- Rate = 90,000
- Duty Cycle = 50%
- Idle State = start state of active edge of SSI clock (ie.. If active high, idle state should be low)
- Continuous Samples
2) Commit this task - this will set the output line to it's initial state
3) Create timed digital input task with following settings:
- Line (pick a port 0 line)
- Sample Clock Source - Counter task's output
- Sample Clock Active Edge - idle edge of SSI clock
- Continuous Samples
- Start Trigger - Digital Edge sourced by counter output task, active edge idle edge of SSI clock
4) Start digital task
5) Start Counter Task
6) Read Data in multiples of 25
7) Process each chunk of 25 samples into a single encoder reading.
In general, I think that it would look something like the VI I have attached (assuming that you're using port0/line0 as a digital line, and the SSI clock is rising edge active. I don't have anything to test this with so I wouldn't necessarily expect it to work, but hopefully it'll lead you in the right direction.
Dan
02-05-2015 08:15 PM
I have a question to ask you .
I have a linear 24 bit ssi encoder,it is a temposonics RH series(MTS),and the signal is differential,and I have the USB-6343 that has 4 counters,I use counter(CO) to generate the signal ,and use DI to get the DATA.but now I have the question below:
1、The CO ("clock") task should probably include two lines, since the encoder is expecting a differential clock signal,and how should I to connect the lines between the USB-6343 and 24 bit ssi encoder,and the same as the data I get.
2、should I care about the voltage when I connect the ware between the USB-6343 and 24 bit ssi encoder,as it is said the ssi interface is RS-422 type differential signal pairs.
Best Regards,
fei
02-06-2015 08:47 AM
Hello yf49782341,
This forum post is from 2011 and it is unlikely that original participants are still monitoring it. In order to maximize the potential for help from the forums it would be best to create a new forum post with the relevant details about your application and detailed questions. This will give your post much better visibility and a better chance of being answered.