M P G control

[Al_The_Man]

Across the COIL, the cathode or stripe to whichever end of the coil the positive voltage is fed to.
Make sure before connecting otherwise you will blow something.
http://www.jaycar.com.au/images_uploaded/relaydrv.pdf
The bar across the diode is represented by the stripe.
(Thanks to Ben Franklin, the check valve symbol for the diode is backwards!).
Al.

[Al_The_Man]

I was having a hard time finding the chip you are talking about so I am going to just order the line drive output mpg wheel and switch them out.

Update on RS422 line driver, DigiKey has a 2 channel 8 pin IC DS9638 for around 70c.
http://search.digikey.com/scripts/Dk...296-15059-5-ND
Al.

[rppman]

Ok thanks Al. But as usual I am a little confused on how is needs to be wired? I looked at the dwg. In the pdf file but I think it raised more questions than answers. I know this is asking a lot but is there any way to cut and paste that dwg in here and mark it up? If not that's ok, and thanks again for the update. I am about a week away from firing this thing up for the first time. Hopefully no smoke!

[Al_The_Man]

I can draw it up and post it, basically the 5v supply is Pin 1 the 5v common is pins 4.
the encoder pulse A is in to Pin 2, encoder pulse B in to Pin 3.
The output is pin 7 = /A pin 8 = A.
pin 5 = /B and pin 6 = B.
5,6,7,8, go to the drive or controller, if from MPG.
Al.

[rppman]

That's good enough. Thanks Al you the man. That would save me $60 I was going to pay for a new wheel.

[rppman]

I am thinking about posting all this information over at the Ajax forum because I bet a lot of people would find this information helpful. I just don't know how they would feel about me bringing in info from another site. I know Scott post here quite a bit, and I doubt he would care. I guess if this topic ever gets brought up over there I will pull this thread up..
So basically you could get the mpg2 setup for the following;
Mpg2 $170
Relay. $8
Line driver $1

[Al_The_Man]

I don't know why it would be a problem, its only information after all?
Al.

[rppman]

Ok, so I got the relay wired for the e-stop. I just have one last question. Am I able to use the Ajax mpg brains to run the mpg2? Thanks in advance, scott

[rppman]

Ok, so I finally got the mpg wired with the line driver chip. I am not getting any movement out of he mpg? I know I have power. I am getting 4.75 volts to the vcc connection on the wheel. From there I am getting the same voltage to the a+ and b+ part of the wheel. From there I am getting the same voltage to the vcc,a+,b+ to the line driver chip. The one thing I am not sur if I wired right is, the wheel needs 5v input that is labeled vvc, and the ov which is com for the 5v. Beings the line driver chip needs the same input, I just added the wires and jumped from the wheel +5v to the chip +5v. I did the same with the com. Should the chip have its own power source or was it ok that I did this. According to my multimeter gage I have power in all the places I need it. Just not sure why I am not getting any movement.

[Al_The_Man]

The MPG and the IC can both share a common supply, I would first see if you are getting a transition out of the MPG without any hook up to the IC, a meter from common to A should see a transition from ~0v to 5v when turned very slowly, the same for B.
You need to see this first before hooking up to the IC.
The IC circuit can be checked by alternately take an input to common and then +5v, you should see the differential outputs both switch polarity.
Al.

[rppman]

So I shouldn't be getting any voltage out of the a or b from the wheel outputs unless it is turned?

[Al_The_Man]

You could be getting 5v in the static state, but they both should go to zero in turn, when the MPG is rotated slowly.
Al.