Messages

181

General Mach Discussion / Re: No VFD voltage...

« on: January 20, 2009, 11:39:20 AM »

Yes - I am sorry. I have now read through the complete PDF file for the combo board - and it leaves me baffled.

A picture paints a thousand words is the saying - a wiring diagram would certainly have done 500 of those.

Without a board in front of me I find it very difficult to go much beyond what I was saying - other than find out what signals your VFD requires first, don't start at the Campbell board. Then work out what is going to procide those signals..

Failing that I can recommend the Digispeed. This is a seperate board, it works on a single wire (plus 5v and 0v) and provides the 0 - 10v output. It uses PWM. You can control the M3 and M4 outputs on the Campbell board (although I found even that hard to understand, and would have to look at it again.)

182

General Mach Discussion / Re: Ready to go with CSS - help!

« on: January 20, 2009, 10:59:50 AM »

Hi Hood -

It works, in that if you set it going , as the tool moves in towards the centre, the spindle speeds up. That's fine, but how do I "calibrate" it. I just tried setting it going at the correct speed for the distance of the tool from the centre, but that is not working.

I am wanting to spin about 200 rpm 50 mm from centre and speed up as I go in (or vica versa, because I am cutting from the centre, outwards). The spindle I am using is max 605 rpm (probably too low, but I need the torque at the low speed).
 
I go G0 X50 - G96 S200 M3 - M1001( macro to call my cutting program) - but all I get is "speed too great for pulley, setting Max" and off it goes at 605 rpm, and it doesn't slow down. I see the CSS led is on with a number isn the DRO but I have no idea what it is.

I'll have another fiddle.

183

General Mach Discussion / Ready to go with CSS - help!

« on: January 20, 2009, 05:36:45 AM »

I've been busy over the Christmas and New Year -

New computer - to replace the laptop - second hand tower.
Touch screen
Ball Screws fitted
Change everything to metric !!!!!!!!!!!!!!
New pulley system on the spindle drive to give equal steps up the pulleys and get maximum power out of the spindle VFD
Rewire all the auxiliaries (home switches and speed detection)
Wire in removeable touch pad.
Get the spindle speed control working relaibly and accurately.
Video camera in the milling spindle.

READY TO GO 

NOW - I am cutting railway wheels - which means facing across a 6 or 7 inch wheel (3inch radius). If I am using Constant Surface speed, how do I set about it. I know how to get it working - I have "dabbled" a bit with it - but if you are to set up an accurate speed, how do you do it.

Does Mach know that X0 is the centre of the lathe and therefore can calculate the correct speed (given the material)
or - Do I have to set the lathe at a distance from X0 - say X25 - and then do an S command to set the speed at that distance - and Mach will then follow adjusting the speed as I move in or out.
or - Is it something different


HELP 





 

184

General Mach Discussion / Re: Probe plug in what is "maximum z height for stuck probe" option do?

« on: January 20, 2009, 05:18:59 AM »

I don't know anything at all about the probe plugin -

But what I always do with new code or anything new on a machine, is put a piece of material (usually a bit of flexible plastic tubing ) that approximates the tool, (or in thsi case your probe) and have a go. At least if if hits anything, you wont hurt it.

I have a simple probe, which works very well and stops on a plate using G31 instructions, but have not tried anything more adventurous.

185

General Mach Discussion / Re: No VFD voltage...

« on: January 20, 2009, 05:07:36 AM »

Bill -

I'll have to answer, just to assure myself you are saved!!

This is probably no help to you - but just a bit of waffle - it might help.

Mach 3 can put out two types of spindle control - PWM (pulse wave modulation) or "Step and Direction" - in both cases, the signal put out by Mach3 has to be converted to a signal your motor controller understands. The choice of system is decided on Config/Ports and Pins/Spindle setup - top centre - motor control. If you tick "Use spindle motor output" you can them tick which system you wish to use.

Mach 3 than puts out the appropriate signals on pins as designated on Config/Ports and Pins/Motor Putputs - at the bottom under spindle (dont forget the port number or you get nothing). In the case of PWM only the "step" pin is used (direction comes out on two other pins under M3 and M4 instruction). If Campbell requires you to use "Step and Direction" then fill in both pin numbers. (Make sure Output is enabled.

That is it for Mach - no other ticks are required.

Coming to the interface with your Spindle Motor, I will describe the PWM first.
PWM is a square wave siganl at a fixed frequency i.e. it is either on "5v" or off "0v". How much of the time it is on or off is determined by the speed you want the spindle to rotate at. In my case this signal (which is on pin 1 in my system) is fed into a Digispeed comverter (Australian - see Digispeed on the net) which changes the signal into a voltage (between 0 - 10 v)  which is fed to the VFD. On my system the VFD supplies a 0v and a 10v wire to the Digispeed, and the return wire gives the corresponding voltage signal back.

On the Campbell board (I have just looked at the PDF) he has gone for "step and dir" system of control - and I think I have found an error in his instructions.
You have ticked the box "Use Motor Control" which is fine - and, I assume, you have set up pins 1 and 14 correctly on the Motor Outputs page.
What you DO NOT need to do is untick "disable spindle relays" and enter into the M3 and M4 boxes "output #1" and subsequently allocate output 1 to a pin number on the Outputs page.

As far as I understand it, if you enter pin numbers on the Motor Outputs page that is all you need. The direction signal will come out of pin 14. You do not need to repeat that - indeed it is counter productive, because, as far as I can see, both M3 (clockwise signal) and M4 (CCW signal) are allocated to the same pin - so you will get the same signal regardless of which direction you wish to motor to go. Try it with "Disable spindle relays" ticked and then test what signals are coming out of pin 1 (you can test this with a volt meter) (if you have access to pin 1 on the break out board) and pin 14. Pin 14 should change from +5v to 0v (or vica versa) when you select M3 or M4. If you have the speed of one of your spindles set to 1000 rpm, and then type S1000 M3 in the MD! line, you should see 5v appear on both pins. (You might see less on pin1). If you type in M4, pin 14 should change voltage. If you type in M5 both should go to 0v.

I do not then understand what Campbell does with  the outputs to your VFD. On mine there is a speed signal (0 - 10v) which I have already dealt with. There are then two seperate inputs (four wires - in two pairs). If a pair is connected (using a relay) I get M3, if the other pair is connected I get M4. If neither are connected I get nothing, BUT if both are connected I get an error since both M3 and M4 cannot (and must not) be signalled together to a VFD.

I could go rambling on, but I think I have said enough at the minute - come back if you don't get it fixed.



 

186

General Mach Discussion / Re: Can anyone help me change the "Goto tool change button" to be more specific?

« on: January 19, 2009, 01:20:59 AM »

If you look at the Video Tutorials on "Scripting" there is a video that shows you exactly how to do this.

187

General Mach Discussion / Re: Losing the will to live :-(

« on: January 19, 2009, 01:03:00 AM »

Same comments as the others - BUT if you are in UK have a look at the drives on Arc Euro Trade.

With the plumeting pound, Geckos are now expensive, and at the recent Midlands engineering exhibition there was opinion that the Arc drives are as good as Gheckos, but also have better inbuilt safety protection.

I have two Gheckos and a 2.5amp one for the Z drive. I am giong to replace the Z and will probably try the Arc Euro Trade.

188

General Mach Discussion / Re: G41 and G42 Help Request! Example given

« on: January 18, 2009, 01:33:32 PM »

As with Hood - I am not sure whether the compensation has been sorted in turn, or not.

The "jagged" edges on your tool display are becasue you have a a G61 - exact stop instruction in your code.

In continuous velosity mode, one line begines, before the last line finished, and the software medls the acceleration and deceleration into one continuous movement. In exact stop, it does what it says - one line comes to a stop before the next line starts.

CV tends to smooth out arcs (it never reaches the finish and start points), but constant velocity cuts it as you wrote it.

189

General Mach Discussion / Re: Does Mach calculate accel/velocity rates for G53 any different than G00

« on: January 09, 2009, 02:35:10 PM »

The machine keeps its position in Machine Co-ordinates. The 0.0.0 position is determined by the position of your "Home"switches - if any. If you do not have home switches connected then the machine will "Ref All Home" anywhere.- but for this explanation we must assume you have them fitted.

The "Home" position will probably not be relevant for machining, and certainly not relevant to your "program co-ordinates" position. To set the program co-ordinates position, you jog to the 0.0.0 position of your program and zero the DRO's for each axis. (NOT Ref All Home - but the zero x zeroy etc,) If you check the Program Co-ordinates position, this will now show 0.0.0, whereas the Machine Co-ordinates position will show the offset of the present position from the machines "Home" position.

A G0 move is relative to the Program Co-ordinates 0.0.0 position, whereas a G53 is relative to the Machine Co-ordinates position.

G53 is "Move in Absolute Co-ordinates" and is used where you want the machine to move to a particular position (relative to the machine co-ordinates) for a specific purpose e.g. tool changing, irrespective of any other offsets (Program or Tool offsets) that are being used. It should not, as far as I know, be used for general machining purposes.

Using G0 you can then take advantage of Constant velocity, where the next line commences moving before the present line is finished, and the program melds the two into a smooth change of directio i.e. constant velocity.

Using G53 - this cannot take place, because the overriding instruction is go to a specific point (and in constant velocity that point is never reached)

Without Constant Velocity, cutting arcs, which on most Cam programs are made up of many, many little straight lines, each line must complete and STOP, before the next line can start, giving a very jerky movement, and this is the effect you are seeing.

I suspect you have the 0.0.0 position of Machine and Program co-ordinates co-incidental, and therefore, although I don't know why, you are using a string of G53 commands for general machining. Being co-incidental doesn't matter - it is using the G53 that is making the difference. G53 should only be used for single movements to specific places.

190

General Mach Discussion / Re: jogging with multimedia keyboard's volume control knob

« on: January 05, 2009, 01:39:08 AM »

The jogging function is not analogue, it is digital, i.e. the speed of traverse is set in the motor settings page. All the jogging arrows do is tell the computer which axis to move in which direction.

I use both Mill and Turn and I find the Turn jogg much better, in that it jogs at full speed if you press down the shift key, and when you release it, it drops to the speed setting percentage. This is not available on Mill, but I feel it would be of great advantage (unless I have missed something)