BiSS Serial Protocol

[alexBC]

Bmann, maybe this is trivial to you, but make sure that you feed the RS422 driver from one of the sbRio 5V pin, otherwise you will get erratic data loss due to problems with the digital reference level.

[bmann2000]

To communicate with the Renishaw read-head, I got the VHDL IP from BiSS for free (Marko.Hepp@ichaus.de), I've targeted this to the sbRIO using IP Integration Node.  Not tested yet as I've to finish building the 422 driver board.

[jbevan]

alexBC and bmann2000

My name is James Bevan and I am the Resolute Application Engineer at Renishaw.  I would be very interested in the work you are doing with the BiSS-C interface and the Renishaw encoder.

My email address is james.bevan@renishaw.com please contact me to discuss your project/application.

[bmann2000]

It was not possible to use the IC-Haus supplied BiSS IP (VHDL) with the LabVIEW IP Integration Node.  The supplied BiSS IP used a series of VHDL files in a format not compatible with IP Integration Node.  Engineers at NI and Renishaw are aware of the end goal, I understand NI were doing some work with the Renishaw BiSS interface.  A plug-and-play solution may become available in the future.  Renishaw/NI are aiming to provide suitable IP to NI developers who are thinking of specifying a Renishaw encoder in their design.

[grivilla]

Hello there,

We also need an interface to the resolute absolute encoders using NI-FPGA devices. Please tell me if you hear anything new about it.

Thank you very much

[PaulieQ]

Hi,

The BiSS-C interface that can be found in the resolute encoder is a basic one (unidirectional).

If you already have a SSI code you can easily adapt it to fit for BiSS-C. You simply have to add one additional bit at the begining (is all the time 0 for unidirectional) and a CRC code at the end. For test purposes you can even ignore CRC bits, but you still have to read them.

If you have a NI bord you can write a short VI that sends a clock. For one frame you need: 1 x start + 1 x "0" (unidirectional) + 24 x data + 5 x CRC + 1 x CDM -> more than 30 bits (Please check the 24 and 5. I don't remeber very well what are the values for resolute). You can send more clocks if you are not sure. A timeout will occur if you send more bits than necessary.

Try not to read the entire Biss documentation. You'll get lost in it. One needs less than 1% from the hundreds of pages from the official website.As I said, start from a SSI and add one bit at the begining and CRC. This is everything.

I hope it helps.

Paulie

[bmann2000]

Please keep requesting a NI compatible driver from Renishaw, they're going to have to oblige soon, they know they'll sell more encoders if they provide a driver.

[grivilla]

Thank you very much for the information. Unfortunately I won’t have the time to test it.

According with NI-Support Germany, NI does not speak about new developments, so no idea whether NI will provide a solution soon or late or never.

 

Thanks again.

[bmann2000]

note that Renishaw associate company RLS now have the E201-9S available.  May be useful for early integration tasks.  It's a SSi to USB convertor.

http://www.rls.si/default.asp?prod=e201&utm_content=789517&utm_campaign=Monthly+Encoder+email+-+May+...

[grivilla]

@bmann2000

thank you very much for the information. in the mean time I've got the following information from NI-Support, Mr Bill Allai:

"Yes we have support for BiSS in the works. The HW module to support BiSS (and other absolute encoder protocols) for our cRIO platform is already completed. Our release is tied to the SW development. Our current release timeline is August of this year with BETA SW available in July. "

so, it seems there will be a solution for BiSS.