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Author Topic: Mach 3 with C-10 BOB... on a lathe?  (Read 2344 times)

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Mach 3 with C-10 BOB... on a lathe?
« on: June 23, 2016, 07:15:13 PM »
I'm very new at CNC in general and Mach 3 in particular, so forgive my ignorance. :)

I'm working on a lathe conversion (typical steppers-and-ballscrews) and trying to get it to run under Mach 3. I have a pair of MicroKinetics drivers (older, but they work- or so I'm told) connected to a CNC4PC C-10 breakout board.

I have the BOB wired to the drivers exactly like this example (.pdf image) since my drivers show an identical diagram (another .pdf, page 6, left image) as that first images' sample Gecko.

I have the C-10's jumpers set so pins 2-9 are output, and the COM terminals are +5VDC. Both drivers and BOB have good power.

At the moment, the build is still only partly completed, so the steppers are "loose" (not connected to the screws, so I don't have to worry about anything crashing) and the limit switch terminals are just jumpered. I have a simple toggle switch temporarily wired in acting as a makeshift "E-stop".

The C-10 comes with an XML file for it, and choosing that with Mach 3's "Loader" gets me a 4-axis mill window.

Now, the two problems: First and foremost, I'm getting no response from my steppers. Trying the arrow keys and/or Page Up/Page/Down changes the DRO display, but doesn't produce any movement at the steppers.

I'm reasonably certain- but not positive- I have the drivers wired correctly, and I'm assuming the XML has the motor pins properly activated. The E-stop does, in fact, work, and when activated (the switch opened or "off") gives me an alert on the Mach screen and blinks red on the "Reset" button.

I checked the motor configuration, and they agree with my wiring (pins 2-3 and 4-5) on the BOB.

The other problem is simply that it's a mill profile, and I need a lathe profile. Is there a way to... import? Convert?... the C-10 configuration file over to the lathe profiles? Or do I need to somehow figure out how to set the lathe profile configuration setting manually?

Thanks for any help you can provide.
Doc.
Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #1 on: June 24, 2016, 12:31:31 PM »
The drivers must have a ground connection. Your diagram does not show a ground to the driver.
Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #2 on: June 24, 2016, 03:03:30 PM »
Please forgive my ignorance, as I'm not very electrically inclined. I have a full size photo of the wired BOB and drivers here. I'm still deep in the building stage so for the moment, the limit switches (terminals 12/5V at the right) are simply jumpered, and I have a simple toggle switch temporarily wired to emulate the E-stop.

Where would I put that ground?

Doc.
Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #3 on: June 24, 2016, 07:03:18 PM »
In you picture, you have connected the driver +connection to the C10 board common pin.  The C10 board common can be jumpered for a plus+, or - ,  but they are NOT for supplying power to the driver.

The power supply + and - pins are for the driver supply.  The driver input pins are labeled for STEP, DIR, +5V, HM, ??, GND.

Remove the wires to the C10 common you have connected to the drivers.

Connect the driver +5v and GND terminals to the Power Supply respective +5v and GND terminals.  One of the terminals on the driver is for an ENable signal. I cannot read the terminal identity adjacent to the GND pin, but one of the two will be the ENable. This pin must see a +5v before the driver will power the motors. The enable signal is not high current, and is usually wired from a relay actuated by a "charge pump" circuit. This insures the motors do not receive power until the Mach3 program is fully in control after turn-on. Otherwise, a motor could be accidentally driven causing damage or injury.

CNC4pc sells a charge pump board, and also has the electrical diagrams on their site.

You can temporarily connect the EN pin to +5v for testing, but it should really be actuated as described above.

Your drivers may also have a current setting, which can be set according to the motor requirements.

John

Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #4 on: June 24, 2016, 07:18:13 PM »
That does kind of make sense, thank you.

The unknown connection is "Fault", and is apparently only used to light an indicator if there's an overcurrent condition.

"HM" is "Home", the description from the manual put it as:

"/HOME - used to indicate the HOME step. The home step is a reference indicator
that occurs once every electrical cycle ( occurs every (2 * microsteps)
pulses). This may be used to qualify a home limit sensor. Example: halfstep
operation; microsteps = 2 so home occurs every (2 * 2) = 4 pulses.
"

I suppose I could see that as an "enable", but I don't think it is.

The "Enable" connection on the BOB is, I believe, only for the BOB itself- a connection for something like a key switch or other safety, that allows the board and drivers to be powered up, but no signals will be sent until the connection to the enable pin is closed.

I may be wrong on that, but that's what I get from reading the manuals.

Doc.
Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #5 on: June 24, 2016, 08:00:40 PM »
Yes, the C-10 board has to have the enable line jumpered, it is next to the Power pins. -, +, EN.

Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #6 on: June 24, 2016, 08:17:04 PM »
I've had it jumpered. You can see the short loop at the power terminals at the upper right of my photo.

What I'm not getting is where to add the ground, if do in fact need one, between the driver(s) and BOB. Or, if it's something besides a ground, just exactly how to wire the BOB to the drivers.

Doc.
Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #7 on: June 24, 2016, 09:24:03 PM »
The Main Power supply provides the DC power for the motors, at what ever voltage and total amperage your motors are rated for. It may be 30 to 50 volts DC.

Volts X Amps = Watts. Watts are "Work per unit of time", or a fraction of a horsepower. 746 Watts = 1 horsepower.

The C-10 board operates at +5v DC . It there is not a 5v tap on the main power-supply, you should have a separate +5v P.S. for the BB, and what else you have that operates at that voltage. 

The  C-10 BB "talks" to the drivers through the STEP and DIR signals.
There is no other connection between the drivers and the C-10 BB in the operation of the machine tool.

It is an "open loop" ; there is no feed-back except if there is a fault, and everything just stops. It is all dependent upon the motors being powerful enough to complete the given commands of the program. Most machines work just fine, as the motors are chosen to have sufficient torque and RPM to move the machine as required.

The C-10 receives the steps and direction commands from the Mach3 program through the parallel port cable, and sends the signals to the proper axis driver.

The DIR signal is either HI (+), or LOW (-  zero volt) . If you read up on the signals, it is actually a specific voltage range between 0 volts, and +5 volts, not precisely 0 or 5 volts. This is the "Direction" signal.

The STEP signal is a frequency which corresponds to the motor speed, in pulses per second. The set-up program in Mach3 determines how many pulses is equal to a given unit. This "unit" is either INCH system, or Metric. It also is dependent on the ratio between the motor shaft rotations, and the distance the given axis moves per the leadscrew pitch.

Stepping motors make a specific number of steps to complete one rotation, and thus you can calculate the "steps per."

Mach3 reads your G-cocde.
Mach3 talks to the C-10 BB; turn such and such axis this many steps, at this pulses per second.
The C-10 BB talks to the drivers through the STEP and DIR signals individually, or all at the same time.
The drivers talk to the stepping motors, as per told by the C-10 BB; direction, how fast, stop, start.

The power supplies are usually 110v AC. The AC ground is not the same as the DC ground. Be sure to have the P.S. chassis ground connection to a good AC ground from the 110v source. This will help eliminate electrical noise, which is always a problem with low voltage signals, like the step/dir signals, and the limit/home switches. Try to make the limit/home switches 24 volts, as it is more immune to noise. There are nice, simple little boards made that will drop a 24 volt signal to 5 volt to connect to your inputs signals for homes and limits.

 

Re: Mach 3 with C-10 BOB... on a lathe?
« Reply #8 on: June 25, 2016, 12:40:35 AM »
Um, yes. Not to sound rude or anything, but I'm not quite that green. :D

I'm sorry, I had interpreted your first post as needing to add a ground. When you then mentioned that I should remove the COM wires, I assumed you meant "... and move them to another terminal". That kept me confused for a bit longer.

I removed the entirely, and it's now working. The steppers are responding nicely, and I believe I can now start setting the rest of the parameters.

Thank you for your help.
Doc.