could someone post a example of how to connect a absolute encoder to a micrologics 1200?

Have done this with a incremental, but not quite sure how to accomplish this with a absolute.
Have used a omron cqm1h in the past with a absolute encoder connector to a expansion card for a absolute encoder, but need to advice on how to do this with a micrologics

Do you have the part number of the absolute encoder you are looking to hook to it. I have not used a absolute encoder but quick search of them reveled some differences in their output signals.

Looking at an AB absolute encoder I looks like Synchronous Serial Interface (SSI). Now Peter has just begin hitting the surface with me on what the SSI is but if the encoder you are looking at has this type of interface then the real question is can we write logic in the Micrologix to read the SSI or do we have to do this with a converter of some type

Then there appears to be binary and Gray interfaces. These can be done with the Micrologix as long as the encoder you select has the proper voltage to interface with your Micrologix

Was out of the office for a few days, when i get back on monday will get the exact part number. It is a omron grey scale encoder.

On some of the equipment that we have, it is important to know what angle something is at if for some reason it has to be stopped, or the estop is pushed. The best that I can tell, you have to have a absolute to do this.

I have a couple of machines that have the micrologics 1200 plc in them, that I am looking at possibly mounting a encoder and using with. It is possible, that i may could replace the plc, but prefer to not have to do at.



Thanks





TW
Is it possible for you to post a example of how you connected a grey scale encoder to the micrologics series.
I can use any brand of encoder. I have the omron, but would prefer to use a ab encoder, since it will be a ab plc.

Thanks

With little Micrologix knowledge, I can tell only who this is done with Logix platform:
Use 1734-SSI module with Ethernet, ControlNet or Devicenet adapter.

how many bits do you need. also, if its a Grey scale, you'll need to write a bit of code to convert from Grey to Binary (its not the same)

Are the inputs sinking or sourcing on the encoder? If they're open collector (sinking) you may need pullup's on the I/O depending on your wiring for the micrologix. If you do use pullups don't forget to invert the i/o (off is on and on is off)

if you need the conversion routines request them and I'll post the link

Need to know the specifics of your Omron encoder. Mainly the type of output to determine if it is compatible with the Micrologix.

As far as ot being AB, Omron, BEI, Dynapar, etc it doesn't matter. Just what type of output it has

Why do you need the absolute encoder?

The encoder I used on the project was a omron E6C3-AG5C-720

I will try and attach the data sheet.

The reason I used a absolute encoder, is the fact the operation of the machine required that if for some reason you hit estop, turned power off etc., when you put the unit back into operation, it had to know what angle the main motor was at, so that once it was put back into production from a estop, etc., it would complete the operaitions at the proper cam angle, as the machine finished the cycled.

I could use any encoder. It does not have to be a omron, the omron is what worked with the omron project.



I would use a ab encoder with the ab plc.

would be interestd in any sample code that you may post.



Thanks





could you post the link for the conversion routines?
Thanks

The conversion routine is illustrated in the PDF you posted

Look at the GCD instruction. I have never used it but I am thinking that you would take your inputs (8,9,or 10) and move them to an integer.

You would need to do a little manipulation for that part but it would not be very hard. Quick summary, can get into details later, would be to first do a MVM on your inputs with a destination of an integer. Then we would divide that by a number depending on what the first input number is to shift these but from their current position to 0-7. Then we should be able to use the GCD instruction to put into a value. Then multiply it by some scaling factor to put into terms that make sense.

Shouldn't be hard

What is the part number of your Micrologix?

Since you have a resolution of 720 on the encoder you'll have to pay attention to the note in your posted PDF. After the GCD conversion you will have to subtract 152 from the result to get 0 - 719.

1762-L24BWAR

That should work fine

If you havent's already wired the 10 bits of the encoder to the Micrologix it would be best if the Least Signigicant Bit is at bit 0 of a word and the Most Significant Bit is at bit 9. (For example I:0/0 through I:0/9)

If there are other inputs connected to the same word then you can use an AND to move just the needed bits to an integer target (for example - AND I:0 03FF N7:0). This would preserver just the bottom 10 bits.

Then use the GCD instruction as TWControls pointed out (GCD N7:0 N7:1).

Finally subtract the 152 (SUB N7:0 152 N7:3) to end up with 0-719 in N7:3.

This subtraction is necessary any time a count which isn't a power of 2 is transmitted using a Grey code. The number of bits to represent the next higher power of 2 must be used. The next higher above 720 is 1024 taking 10 bits. Since the actual code is using 720 of these there are 304 unused codes. The active codes are positioned in the middle of the 1024 codes. So the lowest is 302 / 2 counts up from 0 or 152.

The only catch to putting it on inputs 0-9 is you will be using you high speed inputs. I don't know if that will matter or not in your application but I figured I would note it

Also I don't know what else this project involves but you do realize you will only have 4 inputs to work with for other logic don't you. You might want to look into expansion modules

thanks for replys
got redirected in another direction, have to finish design and installation of a autoclave machine, will get back on this after that.
The replys have been very helpful.
Will plan on using a micrologix 1200 and expansion input module to dedicate to the grey scale encoder, when i get back to this

Thanks