Interface that converts a Gray code to Position information

[Anshu]

I have a position encoder, that outputs a 13 bit gray code. Please suggest a circuit interface that takes this 13 bit gray code as input and outputs the poistion information directly.

thanks

Anshu

[Jochen]

Anshu,

what do you mean by "that takes this 13 bit gray code as input and outputs the poistion information directly"?
Do you want to convert the gray code to a binary representation?
Do you need a parallel or a serial interface?
What do you want to do with the data? Do you want to read them with a PC?
What's the maximum conversion speed?

Best regards,

Jochen Klier
National Instruments Germany

[Anshu]

Well Jochen,

I want to process this gray coded output of the encoder by taking that in my processor. I wanted to avoid seeking in a 13 bit number using a parallel interface. So I wanted to know of a module or device or chip that seekd this input and converts this into a position info.

I would preferably use a logic to extract this info. For eg. let us say if we have a 4 bit gray coded output, the minimum of this number is 0000 while the max can be 1111. There are 2^4 numbers given out in one revolution. Hence 360 degrees is divided in 16 parts. My device will observe a change (which will be a proper sequence of numbers) and increment the output by 360/16 degrees.

I hope i made the problem clear,

thanks

Anshu

[Jochen]

Anshu,

thank you for the information. From NI we could only offer a FPGA based solution for your needs but this would be extremely oversized.
You should search some semiconductor vendors. E. g. LSI might offer such a device. I'm not sure if they have exactly what you are looking for but I know that they have converters and utility chips for a variety of encoder protocols.

I hope that helps,

Jochen

[Anshu]

Jochen,

Will you be programming the FPGA for this application ? If yes then how will the chip look like? How much will it cost. wat will be the time of delivery. I am based in Bangalore, India. Can you connect me to some guy in bangalore, India.

thanks for your inputs.

rgds

Anshuman 

[Jochen]

NI doesn't offer FPGAs but plugin boards (R-Series) and backplane systems (cRIO) that provide analog and ditigal I/Os to create sophisticated control solutions. The FPGA can be programmed with LabVIEW FPGA. Of course from a technical point of view these products could do the job but I don't think that this is exactly what you are looking for.

Jochen

[BuddyHaun]

I have used NI digital I/O cards to convert 14 bit grey code absolute encoder outputs to absolute positions successfully by wiring the outputs two two 8 bit ports and reading the ports and converting the binary gray code to a numeric. You need to make sure you fill the unused lines in the port with boolean false. The application I had could use an inexpensive card due to the slow rate of change but the higher performance cards should let you trigger on data changes at a high rate. The vi for the actual calculation of gray code to binary is on Developer Zone and I am also attaching it.

Regards,

Buddy Haun

CLA