Messages

11

General Mach Discussion / Re: General Config “Charge Pump ON in Estop”

« on: July 26, 2016, 12:17:37 AM »

The "Charge Pump" is an actual device that can recognize the 5khz signal output by Mach3. It is wired into the outputs per the Ports and Pins using one of the output pins. It runs on 5 volts, and when it sees the signal, it operates a relay. CNC4PC sells such a device, and also some of the BB have this capability built in.
The CNC4PC Charge Pump also has a red LED that turns on when the signal is received, making setting it up much easier.

As I said in a previous post, you can select whether the "Charge Pump" stays on during an Estop. The Charge Pump relay is commonly used to control the EN "enable" signal on the drivers, thus keeping the machine in a no-motion state until the Mach3 program is loaded, and has control over the Drivers.

It is not necessary to wire the drivers power into the Estop switch, as the Estop state is seen by Mach3 as a "no steps output allowed" condition, and the motors cannot move.

The Estop is an "Input" signal to the Mach3 program, and the "Charge Pump" signal is an output signal by the Mach3 program. They are two entirely different things in the operation of the Mach3 program operation.

Thus, the "Charge Pump ON in Estop" allows the drivers to have power, holding torque and position during the Estop condition, since the Charge Pump is in control of the 5v. Enable signal to the Drivers. This assures the machine current position will not become altered due to a power-down state of the drivers.

Most stepping motors are 200 full pulses per revolution, but micro stepping settings break this single magnetic pulse into more "partial positions" in the magnetic field.  If your machine is put into Estop, and the motor happens to be in a "partial step position" due to micro stepping, a full Driver Power Off state will lose this partial state position. When power comes back ON, to the Driver, the motor will assume the closest full step position, and not be in the same position as before the Estop.

The Charge Pump is also known as a "Safety Charge Pump", due to it's function in the machine Start-Up.  If you do not have a Charge Pump wired into your machine, it will still function properly as long as the Driver power is not disabled during an Estop. Since you don't have an actual Charge Pump on your machine, the General Config setting does not apply to your machine.

12

General Mach Discussion / Re: General Config “Charge Pump ON in Estop”

« on: July 25, 2016, 03:34:10 PM »

It means just what it says.
Mach3 outputs a 5kz signal when the program has control. Activating the motors before Mach3 is fully loaded can result in the machine moving under power, which can be dangerous. Once Mach3 outputs the signal, a circuit board (the charge pump) operates a relay. The relay is usually wired to the Enable input on the drivers. Until the Enable circuit is activated, the motors cannot move.

In the Output menu, the Charge pump has a specific position, and setting for Active Hi, or Lo, and output pin number.

The Estop will disable driver output, but keeping the (Charge pump on in Estop), will keep power on the driver, just no motion, thus holding the current step position.
If the motors are moving rapidly, and you hit Estop, you will likely lose position anyhow, as it may take a few steps for everything to come to a halt. This is why it is best to hit Feedhold first, then Stop.

If the charge pump relay is off (no power to the enable circuit), when the Estop is removed, on restart the motors can take small jump to the closest magnetic pole, which may or not be the right direction.

Mach3 will work either way you set the function.

13

Third party software and hardware support forums. / Re: Encoder mounting bushing?

« on: July 04, 2016, 04:11:01 PM »

I mentioned JB Weld for the very tiny difference between 1/4" and 6mm. However a large difference makes that impractical.
If you can sleeve a 12mm bore or a 1/2" bore to 6mm, that is the best way. It is a lathe job. If you can drill a bushed coupling to 15/64 (.2344), you are very close, but still under;  6mm = .236 . Turning slowly in the lathe, and scraping with a small round file can open it up enough. Of course, the best way is buy a 6mm reamer. They are about 15 or 20.00.

The lovejoy coupling is like a universal joint, and is not a very good alternative. You also want zero backlash.

It's always the little details that take up so much time.

14

General Mach Discussion / Re: Where are tool length offsets referenced from?

« on: July 03, 2016, 12:34:07 PM »

Gary is giving you the right info regarding the tool offsets. By using the edge finder, you have a reliable Zero Home reference tool that is not going to get busted off in a crash. You have to learn to think about the Machine home, and the Work home. They are not the same thing.

They both exist on the machine, and the "Z Zero at the top of the machine travel" is the Machine Z home.

You don't have to worry about making all the tool offsets "positive."  Mach3 will take care of all the math/arithmetic as far as tool offsets. When the program is running, the Z axis readout shows the program depth of a surface or hole, no matter how much longer or shorter one tool is from the others.

15

Third party software and hardware support forums. / Re: Encoder mounting bushing?

« on: July 03, 2016, 12:05:14 PM »

I first thought your shaft/bore difference was 6mm to 1/4". However the 1/2" bore is another problem. If it were just the small diff, the JB weld would work OK. With the larger bore to deal with, your only option is make a bushing to fit the 6mm encoder shaft. This is a lathe job, of course. If you have no facilities, I could make one for you.

The finished bushing can be put into the 1/2" coupling bore using Loctite #271, Red label. This stuff is super strong, and permanent. After it is set, you can drill on through the set screw hole, and run a tap all the way.

The website "stepperonline" has shaft couplings, and the type I prefer have a red non-metallic center piece, with the two hubs engaging the center with alternate teeth. The have many sized of different mating bores, but the 6mm largest opposing hub bore was 10 mm. Then the major OD of the hub jumped from 20mm to 30 mm. The 12.7mm bore is equal to 1/2", but the starting small side was bigger than 6mm. You can check them out. It has lots of steppers and amps also.

John

16

Third party software and hardware support forums. / Re: Encoder mounting bushing?

« on: July 02, 2016, 12:06:00 AM »

This is a tiny difference, about .007/side. However, if you have a lathe with a collet that will fit the coupling body it can be done. Clean the bore with acetone or lacquer thinner. Then carefully coat the ID with JB Weld. Let it set for 24 hr. Chuck it up, and run a 6mm reamer through the hole, slowly. If I can find it, I will post the source of some couplings that will have the metric bore.
 

17

General Mach Discussion / Re: Replacing X and Y with rotation

« on: June 30, 2016, 10:54:46 AM »

Why try to make the part with a X/A rotary motion, when a standard XYZ motion can easily cut the shape? A CAD program can create a .dxf file from the drawing, and a program like CamBam can produce the Gcode from a .dxf file.

18

General Mach Discussion / Re: Replacing X and Y with rotation

« on: June 29, 2016, 12:22:43 PM »

Your project of two axis motion is not a machine motion of X and Y. It is a motion of one axis rotating, and the other axis a linear radius change with respect to rotation.
You can draw it in X and Y coordinates, but a machine as you desire does not equate to the same thing.
In your picture, Y would be a vertical motion, and the X is a horizontal component. Y is always a vertical linear motion; same for X being always a horizontal linear motion.
When the X and Y create a circle, they are moving in a related motion that is a function of the sine and cosine functions.

You need to construct a drawing, where each rotational unit has a corresponding horizontal displacement.
I assume you are intending to use an end mill to cut the material, as the table rotates (the A axis).
If you lay out the drawing on radial graph paper, with a center point, and lines (degrees) radiating outward, and the other axis concentric rings (the X axis), you can plot your proper coordinates. As you turn the drawing about the center point, and measure the X displacement (radial rings on the paper), this is your machine motion.

There may be some CAD program that can do this, but I am not aware of any.  The motion is like a machine cam, that imparts motion to a follower as it rotates.
The method you arrived at your shape may have the ingredients necessary to create your two axis motion in a simple manner.

Also, if you can plot the action in Excel, with the vertical displacement equal to the horizontal motion of the cutter, and the long axis (horizontal left to right) your degrees of rotation, this will yield your coordinates for machine control.

19

General Mach Discussion / Re: Mach 3 with C-10 BOB... on a lathe?

« 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.

 

20

General Mach Discussion / Re: Mach 3 with C-10 BOB... on a lathe?

« 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.