Monster indexer with two 25:1 motors needs help

[steve4460]

Hi guys
Well I just put my home build indexer online . It has two 25:1 motors on each end and my question is how do I get these motors to turn together and in the right direction .I have all the right cables just like the x1 x2 setup . I am using ASD30A-A drives and ASM98AA-N25 motors .When I input MA 320 and MB 320 seperate the motors turn in the right direction just not at the same time . So how do I fix this so it works just like the x axis 2 motor setup ?.

[richards]

Stephan,
I would use the step and direction signals from one axis to control both motors. Because the motors face each other, like the X-axis motors, you'll need to invert the direction signal to one of the motors so that they each turn exactly the same number of steps at exactly the same time, but in opposite directions. The circuitry to do that is not difficult, in fact, it would only take one or two 7404 chips and a $5.00 breadboard from Radio Shack, or other parts supplier.

If you have a Ham Radio operator near by, or someone who likes to tinker with electronics, he/she should be able to design something in a matter of minutes. If there is no one around, email me and I'll send you a simple schematic that would help with the design.

[steve4460]

Hi Mike

I forgot to mention that I have an PRT alpha, It has 2 seperat drives for the X Axis and I am using that same 2 drive setup for the indexer .There shulde be a way to tell the software what to do.Dose anybody know how to do that ?. I have the right cables from shopbot just like what is on the x axis from the drives to the motors .
Could you hook up both drives to the same output chanel on the alpha board?.

[gerald_d]

Stephan, a much simpler solution....

Look at the Wago connecter nearest the motor. There should be 4 wires coming out of the motor and going into the back of the connector. Number them 1,2,3,4 in your mind, starting from one side. Swop either 1&2 around, OR swop 3&4 around. Only swop ONE pair of wires.

Those wires are held in the connectors with spring force. You have to press a small screwdriver into the connector at a right angle to the wire to release the spring clamp force. You will see the hole on the top of the connector for the screwdriver tip. A tiny screwdriver!

[steve4460]

HI Gerald

I have 8 wires coming out of the motor . Also I bought the cables from shopbot and they are setup just like the once for the X axis on the alpha bot. At least that is what I was toled.
Both motors are turning in the right direction when I send the MA , MB comand to them , but I need to be able to turn them at the same time with one comand. Right now one drive is hocked up to chanel A ,and the other one to chanel B .
I would like to do this with just changing something in the software .
Got any idea.

[gerald_d]

Oops, an Alpha - disregard what I said.

[bill.young]

Hi Stephan,

I don't know of any way to do it in the software and would suggest contacting tech support before trying to hook up 2 motors to 1 alpha driver...Gordon might be able to help.

Depending on how you create your indexer part files another option would be to modify your files so that they output the moves as M5 commands, with the same thing in the A and B positions. It would be a pretty simple text replacement...if that would work let me know and I'll put see what I can put together for you.

Bill

[richards]

Stephan,
One stepper motor per driver. Any splitter circuitry is inserted between the controller and the drivers.

[steve4460]

Each motor has its on driver and is hooked up to A and B axis of the alpha board .
Thanks Bill I will try and call Gordan later .

[pfulghum]

I didn't think that A & B could be driven "in sync". Each will be independent.

I'm interested in hearing ShopBot's reply.

[gerald_d]

Out of curiosity, why have two motors? The gantry has two x-motors because it would be floppy with only one - it would go out of square. But, with the indexer, are you concerned that the material will twist or wind-up if you don't drive both ends? If you tell me that the twin motors are to double the torque, then that could be debatable - there is a chance that the motors end up fighting each other when the workpiece is stiff.

[steve4460]

Hi Gerald

The reason for the two motors is that I can turn larger stuff up to about 24" or so and 8' long .
Could I hook both drives up to the same output channel of the alpha board ?.

[gerald_d]

Unless you have a very fancy control system that will balance the currents (loads) in the two motors, you might consider using only one motor at a time.

[steve4460]

Hi Gerald

How come that it works for the X axis ?.

[gerald_d]

Because the gantry is "floppy" and needs both ends to be anchored and synchronised. Nobody is saying that the 2 x-motors on the gantry are because of heavy cuts in the x-direction - in fact, the cutting force in the x-direction is the same force delivered by a single motor. An 8'long, 24" diameter log is not floppy - you don't need something to drive its other end into synchronisation with the first end.

[steve4460]

Well I guess then I have two indexer now .
It shure would look cool having it set up with two motors .

[steve4460]

Just FYI

Scott at shopbot fixed me up in under 5 minutes .
There is a way to set this up in the software , So now both motors are turning the same and together. You can tell the A channel to be a B channel and therefor both are the same .
Once I get it tuned in then I will post some pictures .
Thanks shopbot for exellent and fast support .