Bridgeport Servo Motors–Mach3 Compatible?

[Peter BellParticipant @peterbell11509]

[Peter BellParticipant @peterbell11509]

My son has a Bridgeport CNC series 1 mill dating from 2002 which is fitted with an Accurite cnc controller and servo motors. It looks like the servo motors have an encoder fitted, there are also glass scales which feed into each servo assembly.

As it looks like the servos are self contained is it possito use a breakout board or something like that and use the machine with Mach 3?

Or has anyone has some experience of the machine and is able to point us in the right direction?

Thanks

Peter

[Neil WyattModerator @neilwyatt]

The web seems to think that MACH can even deal with a mix of servo motors and steppers on the same machine.

I suggest asking on a dedicated MACH3 forum.

Neil

[BikepeteParticipant @bikepete]

There is a whole chain of components which must all work together for Mach to be able to drive your (or any) motors:

Mach (which is motion control software on a PC)

interprets your G-code and drives

A breakout board or motion controller (either an expansion card in the PC, or more often a separate circuit board connected by either ethernet, USB or parallel port)

which in turn connects to

The motor drive controllers (usually separate boxes)

which connects to and drives

The servo motors

If your existing motor and controller hardware is OK, you need to work out what sort of input the controller expects, and then find a breakout board or motion controller which can output the appropriate signals. It's simplest and cheapest if your controller can accept "step and direction" signals like most stepper motor drivers do, but if it doesn't there are still solutions.

Unfortunately, I suspect that both the motion controller and motor drives are all combined in the Accurite control – not sure how easy it may be to separate out just the drives and control them from Mach instead.

Like Neil I'd suggest you'd probably do better on another forum for more detailed advice – the Mach forum is at

**LINK**

but for a friendly UK based CNC forum I would try asking at: **LINK**

Edited By Bikepete on 01/07/2016 20:25:28

[Peter BellParticipant @peterbell11509]

Thanks for the replies and especially the breakdown of the componet parts.

Whats the difference between a motion controller and a breakout board? See both advertised.

I suspect your right about the combined drives. Looked at the servos's which are SEM MTS3077 and there is a lot of wiring between the motors and the readout head so it looks shared to me. Was going to put a scope on the wiring but too much! The machine (which is an Ex-Trak) is in really good condition as are the servo's and it all works but doesnt really like G code as expected of 20 year old electronics. Everything is well plugged together, perhaps there is a solution, so I try posting as suggested.

Peter

[jason udallParticipant @jasonudall57142]

“Doesn’t really like g code” ?

Maybe what you need is a post processor..
I am guessing you wish to “update” your control to get away from a proprietary dialect/interface over to mach3
.

Sure as anything that the original control will have lots of finesse between the servo parameters and the cnc/plc
The “break” between the mmi and cnc and motion control and drives may not be accessible but if it is and if the drives are amenable then of course they can be made to move.
Then of course there are the scales..do their outputs exist anywhere tap able in any “standard” format….

Maybe if the machine works..get a work flow that lets you dribble feed gcodes from a mach3front end ( mmi) to your machine?

[John Stevenson 1Participant @johnstevenson1]

Ok fair bit of wooly advise being thrown about here.

First off it's an Ex-trak so it has it's own type of conversational programming hence the reference to not liking G Code and although the machine is 2002 the Accurite controller is very dated and definitely last century.

To further explain motion control and breakout boards. They are different.

The motion controller which in this case is the Accurite will probably be changed to Mach3 or Linux. All this does is it's the visual part of what you are using, for want of a better description, the bit with the buttons on.

The breakout board is the bit that takes the signals from the motion controller and if we take Mach3 as an example its the bit that connects to the computer by a parallel cable or USB cable. At the moment that part will be done by a proprietary board inside the machine, special to the Accurite.

Good news is these can cost from £5 up to £150

Then in the case of Mach 3 that breakout board then puts step and direction signals out to the driver boards, one per axis and from those driver boards power is applied to the motors.

This applies to steppers and servo's alike but mostly the drivers are different [ some modern drivers can do servo or stepper ]

The stumbling block in this case that applies to THIS machine is that those servo drivers already fitted to the machine need an analogue input of 0 – 10 volts for control and not step and direction. This puts an extra component in the way, a board that takes step and direction and converts it to 0 – 10v. Many have been made and so far none have worked correctly.

Servo's can and usually are a bitch to tune depending on the drivers used and with the complication of the analogue input the modern consensus is to replace the driver with a modern unit but then it becomes easier is you then replace the driver and motor with a matched pair of modern units. These are intelligent units that can self tune.

If cost, experience and a learning curve is an issue you can always replace with three stepper drivers and motors.

Cost is lower as is the build because as I say fitting a new set of servo's and drivers as opposed to just replacing a faulty one can be a long journey for a first time conversion.

[Peter BellParticipant @peterbell11509]

Thanks for the comprehensitive and informative reply John.

Thinking about if further after looking inside at the electronics, we dont want to go down a long unknown path with the existing servo's so steppers quickly look vey attractive. We intend using the existing motor brackets and belt drives.

Will 34 nema motors 116mm long be powerful enough, there are aiso 34 nema stepper servo motors which offer more torque at higher speed?

**LINK**

 

A lot of breakout boards offer usb connectivity as per link, or use do we use a standard board and parallel port connection?

 

http://www.ebay.co.uk/itm/401145598119?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Edited By Peter Bell on 02/07/2016 14:39:13

[John Stevenson 1Participant @johnstevenson1]

Peter,

Both those items in the links will work fine for the machine in question

[Peter BellParticipant @peterbell11509]

We like using Mach3 with our Sieg KX3 which has the limit switches individually wired to the breakout board rather than just all being in series and just stopping everything.

This seems very useful to us as it not only stops the machine if you excced a limit it also prevents you moving further in the wrong direction with the chance of damage. But it will only allow movement in the opposite direction away from the limit.

Is this a common feature on breakout boards as lots just seem to wire all the switches in series?

[John Stevenson 1Participant @johnstevenson1]

Peter,

Is your KX3 a USB machine or parallel port cable machine ?

[Peter BellParticipant @peterbell11509]

John,

Itsa parallel port cable machine.

[John Stevenson 1Participant @johnstevenson1]

Mach normally doesn't know what switch has been hit because the parallel port boards are limited on pins.

However the Sieg KX3 in later [ yours ] Parallel port mode and USB mode has special breakout boards that once one switch is hit locks the direction pin so it can only jog off.

The PP card is a special serviced item from Sieg but the USB card can be bought on the open market.

[Peter BellParticipant @peterbell11509]

John,

Thanks for the explanation on the KX3. Its a vey useful feature which we'd like to add to the Bridgeport but the problem is we dont know what to look for on the USB breakout boards as most descriptions dont seem to cover things like that. Can you point us in the right direction or does this board have the features?

**LINK**

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