Inconsistent (?) instructions for wiring encoders

[InsaneEPP]

I bought my 3 990Hs a few months ago and have them hooked up to my servos. I have US digital encoders (e5S-500-375-EG) and they are single ended TTL units, from what I am understand. I printed out the pdf file to hook up the encoders and I it shows a pulldown resister on pins 3 and 5 (not A and not B). Now they have changed their website and they have a lot more info on it. The diagram on the website shows a pull UP resistor for pins 2 and 4 (A and B) and no connections for 3 and 5.

My Z axis servo is acting funny (jumping around and then going to the end of travel) and when I go into the tuning program, the encoder count/position jumps around. I'm thinking I also have a noise issue, but I would just like to get the general wiring right in the first place. I may have to convert my setup to a differential encoder setup, which I *would* have done in the first place if the website info was up at the time a couple of months earlier.

Anyone have some input they could share with me? It's frustrating to have a machine all put together and ready to go, but unusable. I need the machine to be reliable!

Thanks!

[aghobby]

We have get the same problem with the Rutex drives in the past. As Tom from Rutex said *I will never run a real machine with TTL encoder*

The wiring diagram is also different depending of the pdf file....

The way to solve your problem is to use diffential out encoder or use the line driver converter from their website.

USdigital also sell a line driver converter for ttl encoder for less than Rutex.

Here the link for them:

http://www.usdigital.com/products/pc45/

Hope this help,
Alex

[InsaneEPP]

Thanks for the info and the link, Alex. I guess I will have to bite the bullet and get the line driver converter and then rewire all my encoders with 6+ conductor wire. I wish I had known this before as it would have saved me a bit of work and frustration.

Andreas

PS - your website is no longer up

[InsaneEPP]

Also, for anyone else getting something out of this thread, US Digital has a FAQ and some of it deals with noise issues on encoders.

Here's the link: http://www.usdigital.com/knowledge/encoderfaq.shtml

[Al_The_Man]

After installing and wiring up more encoders than I care to remember, and having a share of noise problems etc on installations, I have for a long time settled on one particular type of cable which is in my experience is the cadillac of shielded cables ( for encoders anyway). The cable is Belden 9891 which is actually intended for ethernet use, this has an overall braid shield with 4 individually shielded pairs, with one of the pairs a larger gauge than the others, this I use for the 5v supply pair.
It is expensive cable and I buy it in drums, but I would definately recommend trying to obtain this cable if you want to avoid any kind of problems, a local network installer may be able to help in supplying a few feet.
Al

[InsaneEPP]

Al, that's pricey, hard to find wire alright! I found it priced near $1000 for a 500' roll. I think I will go with a local supplier who has the same spec'd wire. I only need to run 15' for my Z axis, so I don't think I need to go overboard. I will be separating my power and signal cables, switching to differential encoders and going with STP wire on all axes, so the combination should be pretty bulletproof. Any benefit the Belden wire might give me will be negated by having my encoder mounted directly to my servo.