Cheap Encoders - Where to buy?

[UKRobotics]

Greetings all,

Just wondering if anyone might be able to suggest a source of low cost encoders.

I need to replace the old heidenhein encoders on my old SEM motors as they are not compatible with either gecko or rutex drives. The problem is, all the low cost encoders I have been able to find only go up to a shaft size of about 6mm or 1/4" and the shaft on the encoder end of my motor is nearer 12mm.

Ovbiously I could turn down the motor shaft to fit, but this is somthing I'd really rather avoid.

[bill south]

Hey UKR
A great source of encoders is usdigital dot com. They carry most sizes and should be able to help.
Bill

[Al_The_Man]

I assume these are through hole encoders? Why is the Heidenhain incompatible? resolution? or are they the sine wave output type?
Renco should be able to supply an alternative, if really needed.
Al.

[mcpltd]

We have many USdigital encoders in stock, not sure about the 12mm bore though, i will check when i am back in the office.
What resolution are you after?

[UKRobotics]

Thanks for all the replys.

Al - Got it in one. The old heidenhain encoders are sine wave output type and modulate the signal by varying the current rather than voltage.

.. and yes, I did indeed mean hollow shaft encoders

[mcpltd]

We only have 10mm bore disks in stock, but they can be turned out to 12 mm quite easily.
Just note that the E2 encoder is single ended not differential, but we do have a circuit to make it differential.

We also have some Eltra Encoders but they are more expensive.

if you are interested call us on 01202 599922

[Al_The_Man]

Originally Posted by UKRobotics Al - Got it in one. The old heidenhain encoders are sine wave output type and modulate the signal by varying the current rather than voltage. .

The typical Heidenhain sine wave encoders are 1v p/p sine wave output, and Heidenhain use a MC34074 IC on the recieve end.
I would be tempted to place an op amp on the signal and square them up to 5v p/p. If you want differential, put a RS422 IC on the output.
material cost per/unit <$5.00
Al.

[UKRobotics]

Al, you've kinda lost me there. I think I understand what you are saying, but wouldnt know how to implement it.

[UKRobotics]

I went up to the workshop this morning and measured the motor shaft and was pleased to discover that it is actually 10mm rather than the 12 I had previously estimated. This will make fitting the encoders a lot easier.

Also spoke to Gary from MCP and he can supply the right encoders which fit the bill both eletrically and mechanically for about £30 each +vat.

The only thing now is to choose the CPR / PPR.

Does anyone know what encoder resolution I should choose ? I will be using Rutex drives and have been given the choice of either 500 or 1000. Which is better and why ?

[FPV_GTp]

Hi

sorry to intrude here curious to this thread

cheers