Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Nworroll on January 05, 2011, 03:20:59 PM

Title: DC driver board, terminal abreviations?
Post by: Nworroll on January 05, 2011, 03:20:59 PM

Converting an old allen bradley bandit 3 controlled mill to Mach 3.
The current 'DC driver board' in the machine has the following input terminals (one set for each axis)

Sig - LO, H, and SH
Tach - H, LO, and SH
Driver - SH, ENA, FLT, and GND

The Tach has connections going to the motors, for feedback I assume.
The Sig has wires going to the LO and H that go into the CNC computer board.
The driver block has nothing connected to it.

This board has wires going to individual boards that are then wired to the motors.

Can someone just give me a quick rundown on what these are.  I am assuming this is a +/- 10V driver board? and can't be used (directly) with mach 3's step/direction signal?

Thanks

Title: Re: DC driver board, terminal abreviations?
Post by: NosmoKing on January 05, 2011, 04:55:26 PM

Sig - LO, H, and SH    +-10v and  SH=shield
Tach - H, LO, and SH   Tach +ve  & -ve  and shield (tach not needed on modern drives)
Driver - SH, ENA, FLT, and GND  ENA=drive enable input, FLT = Drive fault output GND = Common, each referenced to common.
Nosmo

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on January 31, 2011, 10:44:04 AM

Thanks Nosmo.

The +-10v siganal, is this an analog signal where +/- control the direction and a varying voltage controls the speed (2.5v = 25% speed, 5v = 50% speed, etc)? or is in a 10 V PWM signal input?

Thanks, Nick

Title: Re: DC driver board, terminal abreviations?
Post by: NosmoKing on January 31, 2011, 10:54:23 AM

The info I have shows ±10vdc analogue.
N.

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on January 31, 2011, 11:20:05 AM

Cool.  So if I made a circuit with a adjustable voltage regulator controlled by a potentiometer, a switch for +/- voltage, and a push button and sent that output to the controller, I should be able to have a simple Jog control?  The pot for speed, the switch for direction and the push button for jog.

Anything I am overlooking?

Title: Re: DC driver board, terminal abreviations?
Post by: NosmoKing on January 31, 2011, 12:03:24 PM

Or Conversely you could make dual output supply  +v & -v with common,  and connect a 10k  pot across the +v  & -v , the slider would go to the analogue input and the the drive input common would go to the P.S. common, this way you have bi directional control without switch.
N.

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on January 31, 2011, 12:44:46 PM

That's a good thought as well!  I'm gonna make up a quick circuit for testing and make sure things work.
Is there any worry about sending to much current to the signal input?

Title: Re: DC driver board, terminal abreviations?
Post by: NosmoKing on January 31, 2011, 01:16:19 PM

The inputs are generally high impedance, op amp input so you cannot usually over drive them.
10v max.

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on March 29, 2011, 12:42:42 PM

So I got the thing powered up.  When I jumper the 'enable' input that was running to the original controller, both green lights on the driver board light up and everything seems ok.  I have 3 power wires running to each motor (100VDC rated).  One wire appears to be ground, and I have 100VDC from each of the other wires to that ground. Does this sound correct?
 
The motors can turn freely when it is powered up.

I tried sending power to the signal inputs but nothing happens.  Maybe I am hooking it up wrong. 
If I wanted to just send a +5 volt signal, I would just have to hook up the +5 to Sig H and the ground to Sig LO?  And this should make the axis move correct?

Nick

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on April 01, 2011, 11:09:23 AM

Here are some pictures of the board.
(http://i18.photobucket.com/albums/b147/buicknick72/mill/2011-03-29184918.jpg)
(http://i18.photobucket.com/albums/b147/buicknick72/mill/2011-03-29184902.jpg)
(http://i18.photobucket.com/albums/b147/buicknick72/mill/2011-03-29184925.jpg)

Title: Re: DC driver board, terminal abreviations?
Post by: NosmoKing on April 01, 2011, 12:16:48 PM

If the ready lights are on I would have expected it to run, 5v should be enough to drive it.
If the drive is active, the motors should either 'cage', hold position, or run away, if they have a tach wrongly phased.
You are most likely reading 100v to ground off the motor leads due to high impedance meter reading leakage.
If you are stuck, give HuFlungDung a PM over on the CNCzone site, he has quite a bit of experience with Bandit amps and repairing them.
N.

Title: Re: DC driver board, terminal abreviations?
Post by: Nworroll on April 04, 2011, 08:17:29 AM

I sent him a message, he said he only had experience with older model bandits.  I also posted in the forum, but no reply.
I did a little more testing.  I found that if I put any positive voltage to H, with ground of that voltage to lo, or to the machine ground, OR any negative voltage to LO with the positive of that voltage to ground, then - The 100 volts going to the motor I measured goes to 0V. 
I am changing a part that maybe defect on the board, I'll let you know what happens after I swapped it.