[CATCH22]

I am going to order my encoders to go with my Viper 200 servo drives and I was planning on using the E5 US Digital encoder with 1000 cpr has anyone used these or something else that works well with these drives that they could recommend for my setup.It will be going onto a Excello 604 cnc milling machine.

Thanks Mike

[Larken]

Yes, the E5 (or E6 for bigger shafts) with the differential option works great.
I use a lot of these on our own cnc routers.

For the connector (10pin housing), I use Digikey part# WM8037-ND for the Housing and WM2558-ND for the Pins.
Use twisted pair (stranded) network cable and the 9pin D connector (I supply)

Larry

[Karl_T]

I'll second that. Be SURE and get the differential option. Makes your encoder far more noise immune. i put them on an Excello 602. Almost the same machine.

[CATCH22]

Ok thanks guys, but what is the differential option,and should I go with more than 1000 cpr or is this the best count to go with?

Thanks Mike

[Karl_T]

Ok thanks guys, but what is the differential option,and should I go with more than 1000 cpr or is this the best count to go with?

Thanks Mike

Differential, in my limited understanding, always powers the square wave pulse to either +5 or -5V. The other option is +5 V and not powered. If you have line noise the unpowered period can stay above the 2.2 volt cutoff and you miss a pulse. This is not uncommon. I put the cheap one on my CHNC lathe. When ever the air turret was indexing, it missed pusles and slowly caused the axis to get off. It made out of tolterance parts then. I had to go back and put differential units on to solve the problem.

For count you want a very even number when making small moves so you don't call for paet of an encoder count. My 602 had 5 turn per inch ballscrews so i went with 2000 count encoders or 100,000 count per inch.

Karl

[HillBilly]

Differential noise immunity is based on common mode rejection. The reciever can only detect a difference in the SIGNAL and [U]SIGNAL[U]. If the same noise appears on both lines it is rejected. There is no -5v used.

Darek

[Al_The_Man]

Another spin, a differential has 6 conductors rather than 3, there is a complement signal for each A B & I signal.
See RS422 standard.
http://www.lammertbies.nl/comm/info/RS-422.html
Al.

[CATCH22]

Ok thanks for all the replys, now will it make any difference if I go with 1000 cpr or 2000 cpr. Will it make my rapids slower?

Thanks Mike

[Al_The_Man]

my 602 had 5 turn per inch ballscrews so i went with 2000 count encoders or 100,000 count per inch.

Karl

I would interpret that as .000025" resolution for 2000c/turn enc?
(2000*4)*5 = 40000 pulses/inch. One pulse = .000025"?

The encoder should always be quoted in the basic quadrature pulse for one signal per rev from the manufacturer, the quadrature pulses are then usually multiplied x4 the basic pulses in the drive or controller.
Al.

[Larken]

My 602 had 5 turn per inch ballscrews so i went with 2000 count encoders or 100,000 count per inch.
Karl

Thats 10,000 counts per inch.
(or 40,000 with 4x decoding) but typically you use a 4 x step mulitiplier which brings it back to 10,000 steps /inch

[CATCH22]

It looks like I will have to go with the E6 because the E5 only goes to 1250 cpr. So I will be going with part # E6-2000-375-I-D-D-D-B
There is one more question I have for ordering on the US Digital web site under Configure and Purchase there is the option of No Index or Index (3rd channel) which one of these do I want or does it even matter?

Thanks Mike

[CATCH22]

I just talked to Larry at larken and he has cleared the index issue up for me.
The viper drives work with no index. Thanks again Larry.

Thanks Mike