Bridgeport CNC

[apayne]

Hi,

I have an old Bridgeport mill that was retrofitted back in the late 80's.  It is using a DOS based controller and I would like to get it running on Mach3.  It is using
 MAE HY-200-3450-700 B8 steppers.  would the 340 be able to run these steppers?

[Steve Stallings]

Sorry, but you are going to need a significantly more powerful driver to run that machine.

The PMDX-340 is rated to run motors that require up to 3 amperes. Your motors require
7 amperes.

If the power supply and motor drivers used in your old controller are salvageable, you
may be able to upgrade just the logic portion. This would require a breakout board or
smart interface that could work with Mach3 or Mach4.

[apayne]

The controller still works but it is not compatible with new computers.  can you recommend the break out board or smart interface that I could buy form you?

thanks,
Aaron

[Steve Stallings]

My most likely recommendation would be a PMDX-424 and Mach4.... BUT....
it would be best to know more about your existing controller before you
buy something. Can you provide information about the drivers and power
system, or some photos that would allow them to be identified?

[apayne]

It is a Centriod CNC controller
Model  CNC-B24-MD3
Serial # 1032

here are some pics and it looks to be 1989 vintage.  hope this helps to make sense of it.

Aaron

[apayne]

last pic is the motor controler

[apayne]

Let me know if these pics help or if I need to take the controller apart a bit more.

Aaron

[Steve Stallings]

Your pictures show me that the motor drivers are Centroid proprietary
units that we may have a difficult time finding enough documentation
to understand how to connect them to a modern breakout board.

I think I would recommend that you keep your old control intact because
the drivers in it are proprietary Cendroid units. It might be possible to
figure out how to reconnect them to a modern control system, but then
if anything goes wrong with one of them you are stuck again. The old
controller could be a backup, or would have resale value to someone
else trying to maintain an old system.

Modern drivers and a suitable power supply should cost less than $500
for all three axes and using your existing motors.

I would still recommend the PMDX-424 and Mach4 for running the system.

[apayne]

is there any way to take the PMDX-340 and bump up the amp output to 7 amps with a different power supply?

I did take a simple electronics course in college but would not feel comfortable wiring up anything with our a detailed wiring diagram. 

Aaron

[Bob at PMDX]

is there any way to take the PMDX-340 and bump up the amp output to 7 amps with a different power supply?

No.  Either the built-in protection circuits kick in, or the driver chips go "pop".

[Steve Stallings]

The PMDX-340 was engineered for table top machines using NEMA-23
or NEMA-17 motors. Your Bridgeport with NEMA-42 motors is way
beyond its capabilities. There is no reasonable way to boost the
current output from the PMDX-340 beyond what it was designed to
provide.

If you want to avoid building your control by buying drivers and a
power supply, you can look at complete controllers designed for
larger machines. One example would be:

http://www.cncrouterparts.com/4-axis-digital-plug-and-play-nema-34-system-p-132.html

[apayne]

Thanks you for the information!!  Your controller wont work ont he Bridgeport, but......

I don't think I mentioned it earlier, I am a Metal shop teacher and the Bridgeport is a machine that has been at the school for ever.

We also have a few other older machines that I would like to get up and running, two Orac lathes and a Prolight mill, see pics, that I would like to get running.  Again the current controllers work but are so old they are not compatible with newer computers.  I would like to use the PMDX-340 but I need to do some more investigating to find out the stepper motor amp requirements, but you might know.

Thanks again for all of your help,

Aaron

[apayne]

Here are some pics of the stepper motors on the lathe  and mill.  the first is the lathe and second is the mill.

Aaron

[Steve Stallings]

Now these machines are more reasonable... 8-)

We will need to know if they are 4 wire or 6 wire motors (bipolar or unipolar)
in order to figure out how to connect them and what to use for a current setting,
but I think the PMDX-340 could run either of the machines.

[apayne]

GREAT!!

I think the mill is 4 wire but Ill double check and look into the lathe.

Aaron