[kreutz]

Kreutz / L98FIERO how do the "Differential quadrature encoder interface" work, are they similar to these:

Yes, but I used the SN75115N differential line receiver instead of the other chips, and this one is mounted on the main pcb instead of being an "add on" board.

[kreutz]

Kreutz;

......
When you get the design finalized will you make a description of how to build and test the board for people like myself that are not as familiar with electronics but want to build the board themselves. ......
LaVerne

I will do my best to provide enough information

Regards,

Kreutz.

[contactirfu]

Yes, but I used the SN75115N differential line receiver instead of the other chips, and this one is mounted on the main pcb instead of being an "add on" board.

Then what should be on the motor end, considering i have US digital encoders the cheapest ones, or can u suggest what encoders to buy if i use your new pcb...preferably US digital! (easy to order)

Regards
IRfan

[Dibblah]

Then what should be on the motor end, considering i have US digital encoders the cheapest ones, or can u suggest what encoders to buy if i use your new pcb...preferably US digital! (easy to order)

Regards
IRfan

Presumably, you can use single-ended encoders by just tying one of the inputs (-) to ground.

Cheers,

Allan.

[contactirfu]

Presumably, you can use single-ended encoders by just tying one of the inputs (-) to ground.

Cheers,

Allan.

Allan,

My poor brain cant understand, can you elaborate......ie.,explain a bit.

Thanks in Advance!

[Dibblah]

Single ended encoders are the type you get if you don't ask for differential.

On the new UHU board, I'm assuming that you'd just connect the encoder to the + differential input and connect the - differential input to ground (0v).

Cheers,

Allan.

[L98FIERO]

The differential encoders have 8 wires, a plus and a minus for the a, b and index plus 5v and ground. Some one can correct me if I'm wrong or maybe contact US Digital but I think you may be able to get the tiny LD5 board that I had a picture of in my last post and connect that to each of your single end encoders. My understanding of the 26C31 chip is that it doesn't change the signal but adds an 'inverted' copy of the existing one and then the receiving end converts it back to the original signal. My guess is that you get twice the difference in voltage and therefore a 'cleaner' or at least easier to read signal. If you don't have an index mark on your encoder it obviously won't add one.

LaVerne

[RCruz]

-------wrong user----

[RCruz]

I am sorry, I was visiting Mr. RCruz and posted twice on this forum from his PC, didn't realize it was under his user name. It won't happen again.

Kreutz.

[kreutz]

The differential encoders have 8 wires, a plus and a minus for the a, b and index plus 5v and ground. Some one can correct me if I'm wrong or maybe contact US Digital but I think you may be able to get the tiny LD5 board that I had a picture of in my last post and connect that to each of your single end encoders. My understanding of the 26C31 chip is that it doesn't change the signal but adds an 'inverted' copy of the existing one and then the receiving end converts it back to the original signal. My guess is that you get twice the difference in voltage and therefore a 'cleaner' or at least easier to read signal. If you don't have an index mark on your encoder it obviously won't add one.

LaVerne

Adding a differential transmitter chip (for those who have a single ended encoder and want to use the differential transmission advantages) is easy, I am sure there are a lot of boards readily available, or you can make your own. The receiver I have on board can be left unpopulated (if you don't use differential encoders), and connect a couple of soldered jumpers for your single ended (standard) encoder.

The advantage of using a differential encoder is that it rejects common mode noise, so the signal is cleaner, and the encoder cable could be longer.

Kreutz.

[contactirfu]

Adding a differential transmitter chip (for those who have a single ended encoder and want to use the differential transmission advantages) is easy, I am sure there are a lot of boards readily available, or you can make your own. The receiver I have on board can be left unpopulated (if you don't use differential encoders), and connect a couple of soldered jumpers for your single ended (standard) encoder.

The advantage of using a differential encoder is that it rejects common mode noise, so the signal is cleaner, and the encoder cable could be longer.

Kreutz.

I understand Kreutz, my problem was that I already have a few single ended encoders with me and my cable length is long. COuld you or anyone suggest me a suitable pair(easily available and widely used) in dip package like the one I posted in my earlier post. I just wanted to know whats the IC(transmitter) on the motorside,

I thinkl its easy to build one on a general pcb than order one and wait!

Regards
IRfan

[gilgamesh]

hello to everyone,
thanks all of you for what you are doing here. I am really a newbie to cnc. I have been using large plotters and a small roland mdx 15. I have spent a lot of time for deciding to build up a cnc router. I think servo dc motors and UHU drivers ( or controllers?) are the best solution for me. I just hope to build a small prototype first with the salvages i have been collecting for years. I have 3 dc servo motors from dynetic systems with 24 volts and 3.3 amp. The point is that these motors have only 2 cables and a separate ground cable. But when i check the schematics and pictures from you i see that there are more than 2 connections. Do i need an extra thing ? Is it an encoder ? Or is it ok just with these dc motors. please help?

[kreutz]

hello to everyone,
thanks all of you for what you are doing here. I am really a newbie to cnc. I have been using large plotters and a small roland mdx 15. I have spent a lot of time for deciding to build up a cnc router. I think servo dc motors and UHU drivers ( or controllers?) are the best solution for me. I just hope to build a small prototype first with the salvages i have been collecting for years. I have 3 dc servo motors from dynetic systems with 24 volts and 3.3 amp. The point is that these motors have only 2 cables and a separate ground cable. But when i check the schematics and pictures from you i see that there are more than 2 connections. Do i need an extra thing ? Is it an encoder ? Or is it ok just with these dc motors. please help?

A servo motor is not just the motor, it needs a feedback device. Depending on the application, the feedback device could be a tacho-generator, a resolver, potentiometer or quadrature encoder. If you have a DC motor with just two wires it is probably either a universal motor or a Permanent magnet brushed motor.

One of the most used encoders for positioning servos is the quadrature encoder. They have a minimum of 5 cables: DC return, Vcc, Channel A, Channel B and Index (some of them don't have the Index feature and might use only four wires). Differential encoders include the CHa-, CHB- and I- wires.

[kreutz]

I understand Kreutz, my problem was that I already have a few single ended encoders with me and my cable length is long. COuld you or anyone suggest me a suitable pair(easily available and widely used) in dip package like the one I posted in my earlier post. I just wanted to know whats the IC(transmitter) on the motorside,

I thinkl its easy to build one on a general pcb than order one and wait!

Regards
IRfan

You could use any differential line driver IC with 5 Volt VCC, like the uA9638 type (dual), if you also use the index channel you can use a quad differential line driver chip. Remember to use twisted pair cable for each differential pair.

[gilgamesh]

Thanks Kreutz,

Where can i find information about connecting a dc motor to a quadrature encoder? can i connect any dc motor to quadratures?

[kreutz]

Thanks Kreutz,

Where can i find information about connecting a dc motor to a quadrature encoder? can i connect any dc motor to quadratures?

To find out what are the best motors for servos read this: http://www.uhu-servo.de/servo_en/UHU%20FAQ_en.pdf

For adding the encoder to a DC motor read this: http://truetex.com/servomod.htm

[contactirfu]

Thanks Kreutz,

Where can i find information about connecting a dc motor to a quadrature encoder? can i connect any dc motor to quadratures?

http://www.usdigital.com/products/products.shtml would be a good start.

[Fifty_ohm]

You could also check http://truetex.com/servomod.htm.

[contactirfu]

You could use any differential line driver IC with 5 Volt VCC, like the uA9638 type (dual), if you also use the index channel you can use a quad differential line driver chip. Remember to use twisted pair cable for each differential pair.

kreutz found out some neat data at usdigital

http://www.usdigital.com/data-sheets...0Schematic.pdf
http://www.usdigital.com/data-sheets...0Schematic.pdf

Do you think these will work?

Regards
Irfan

[kreutz]

kreutz found out some neat data at usdigital

http://www.usdigital.com/data-sheets...0Schematic.pdf
http://www.usdigital.com/data-sheets...0Schematic.pdf

Do you think these will work?

Regards
Irfan

They will work.