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Offline SimonD

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Odd Startup Behavior
« on: December 08, 2007, 05:20:22 AM »
Hi,

I am experiencing an odd behavior with my mill...
For the first few hours every morning the following happens and then it seems to cure itself...

I turn everything on and home the mill, all OK.
I set the work offset and tranverse manually to the approximate start position.
I load the program and press start. All of a sudden the X axis is reversed and the cutter goes off in the wrong direction.
I stop the machine and try it manually and the X axis is reversed even when jogging using the keyboard.

I shut everything down and restart MACH3 and start the process again checking that the MDI input to the start position is OK.
the same thing happens 3 or 4 times and then after a few attempts it works properly.

Has anyone had this before?
Thanks
Simon

Offline jimpinder

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Re: Odd Startup Behavior
« Reply #1 on: December 08, 2007, 09:04:32 AM »
This sounds to be a fault with the driver card for the x axis (probably the dir input) which seems to be faulty until it gets warmed up.
Try swapping the inputs with those of the Y axis, and see if the fault moves too - this will tell you if it is the card.

I can't see what else it can be, I assume you have set up your config/port and pins correctly with active low or not as is the case and you do not change these.

If you are using a breakout board with some sort of buffer on, then it might also be the breakout board that is passing the wrong signal until it warms up.  If you have a digital tester you can see what the input is and if the card is behaving as it should.
Not me driving the engine - I'm better looking.

Offline SimonD

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Re: Odd Startup Behavior
« Reply #2 on: December 08, 2007, 10:53:23 AM »
I am using a 3 axis StepMasterNC and a 1 Axis StepMasterNC for the A axis.
It has been working fine for ages.

I have just run a program and it cut flawlessly for 2 1/2 hours. After the program had finished I manually positioned using the MDI screen so that I could drill holes etc. I then loaded a new piece of material, pressed rewind and started the new program and all of a sudden the X axis is going the wrong way again!.

I re-homed all axis and typed in the start coordinates and it went to it OK. I then pressed rewind and start again and it worked!

It is almost as though when the program has finished something is messing up the X axis.
I terminate the program with an M2 command followed by a % symbol on a line by itself. What does this do?

Thanks
Simon

Offline jimpinder

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Re: Odd Startup Behavior
« Reply #3 on: December 10, 2007, 12:55:09 PM »
I don't know about M2 and %, I use M30 which ends the program and rewinds the script.

I still cannot see that this can be anything but a driver card fault. Try using your A axis card to run your X axis and see if the fault repeats itself. If you want you can run the A axis from the old X axis driver and see if the fault shows up there ( I don't know what you use your A axis for). If you need the A axis, then buy a single card and try it.

The motor is running - and since it onlly runs if it receives pulses in the right order we must assume that this part of the driver is OK. Either the "dir" part of the card is faulty, or the connection to it is loose. There is no other explanation.

The only other reason is that your program is telling it to run that way - but from what you say, you have been running the program for 2 1/2 hours and all is well - then it decides to have a thrombosis.

I had Stepmaster cards first - and they seemed to run OK. I had a double card and a single. They went faulty after (I think) I connected the power supply wrongly. I use Routout cards now. (Because the Stepmaster cards were a long time in delivery here in the UK) I use three seperate cards so that if one goes faulty, I can replace it easily. I have protected the power inout side with a diode bridge.

The only other possibility is that if you have a breakout board, then that is faulty.

It is no good looking at the problem - you will have to do a bit of searching to find the answer.


Not me driving the engine - I'm better looking.

Offline SimonD

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Re: Odd Startup Behavior
« Reply #4 on: December 10, 2007, 03:51:02 PM »
I will try M30. The only real reason I went for the StepMaster cards was they were cheap off eBay!

I have found a routine to make the fault reproducable...

If I press the following...

-> the table moves left (correct)
<- the table moves right (correct)
F5 (start the spindle)
-> the table moves right (wrong)
<- the table moves right (correct)
-> the table moves left (correct)

It seems there is still a problem with pin 16 on my PC. (I have had problems in the past but thought they were fixed with a new LPT card)

If I change the relay output to pin 17 then the problem does not appear to happen, as soon as I move it back again it can be tested as above.
I was using pin 17 for my coolant relay but thought that was causing the problem so removed it again and went for plugging/unplugging it as required.

I guess I could try pin 14 but I was using that to get MACH3 to enable the drives. I removed that too because I was having problems with the axis becoming disabled after I pressed stop (not E-STOP) and I could not jog the axis without pressing the E-STOP twice!

Alternatively I could wire both the relays into pin 17 so the coolant started whenever the spindle was on?

Offline jimpinder

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Re: Odd Startup Behavior
« Reply #5 on: December 12, 2007, 03:57:07 AM »
It is unlikely you would get the same problem on two different cards.

I assume you are using pins 2 - 9 for activating the motors, leaving 1,14,16 and 17 as additional outputs.
It would appear that the fault does not lie with pin 16 - which, I assume, switched the spindle on and off correctly, but lies with the "dir" pin for the axis in question.

You say that you press F5 - so I assume this must be set up on your system hotkeys. Check on your system hotkeys set-up and make sure Pin ?? is not inadvertantly set up to also react to F5. (Or indeed on someother program that may be running in the background - although to be fair pins 2 - 9 were only data pins if used with a printer)

Does the fault occur if you use the mouse on the screen ???

If you feel you are running out of pins, and are only using three axis, you can use pins8,9 as general output pins as well.
Not me driving the engine - I'm better looking.

Offline bowber

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Re: Odd Startup Behavior
« Reply #6 on: December 12, 2007, 07:17:28 AM »
I've had a similar problem that I traced to electrical noise.
Mine was also a bit more random, the Z axis would work fine then suddenly it would go up instead of down but the DRO was showing it going down. I had fun with that one for a while till I figured it out  ::)

Your obviously getting somewere as you can repeat it consistently which is the best start.
Perhaps you should strip down to the basics with only the axis being controlled by the LPT and then work back up from there adding the home switches then relays etc until you find the root problem.

Steve

Offline SimonD

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Re: Odd Startup Behavior
« Reply #7 on: December 12, 2007, 03:31:59 PM »
I am using pins 2-9 for Step/Dir on the 4 drives.
Pin 1 is for the charge pump (not yet implemented but planned)
Pin 14 is for drive enabling.

Leaving only 16 and 17, Ideally 1 for Spindle and 1 for coolant.

As I am having trouble with pin 16, I have both relays connected to pin 17 so the coolant comes on whenever the spindle comes on. It is not ideal but it seems to be working OK.

It would appear that the fault does not lie with pin 16 - which, I assume, switched the spindle on and off correctly, but lies with the "dir" pin for the axis in question.

Can you elaborate on that? Why would the dir pin affect it? If I stop using pin 16 altogether then the problem goes away (or at least has not shown itself since disconnecting that pin)

You say that you press F5 - so I assume this must be set up on your system hotkeys. Check on your system hotkeys set-up and make sure Pin ?? is not inadvertantly set up to also react to F5. (Or indeed on someother program that may be running in the background - although to be fair pins 2 - 9 were only data pins if used with a printer)
F5 is the standard key for spindle on. I have not modified the system hotkeys from the standard install.

Does the fault occur if you use the mouse on the screen ???
Yes, if I press the screen button then the fault occurs. (while pin 16 is connected)


I did do a complete strip down and rebuild when I added the 4th axis including completely rebuilding the electronics enclosure/wiring etc. The original system was using the onboard LPT port and I had the same problem. I have installed a separate LPT card now and the problem is still there. I can only assume it is some sort of interference problem on the StepMaster board or within the driver system of the PC.

Hindsight is a wonderful thing. Whilst the StepMaster is a great little card, I appear to have outgrown it quite quickly! When I first started I didn't want the 4th axis, coolant/spindle control or a charge pump!
« Last Edit: December 12, 2007, 03:38:37 PM by SimonD »

Offline jimpinder

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Re: Odd Startup Behavior
« Reply #8 on: December 16, 2007, 10:29:24 AM »
The stepmaster was a good card - I had a double and a single for three axis. I have gone onto Routout, not becasue I think they are better, but in UK they are more quickly available. I now use seperate cards for each drive, so that if one goes, I don't loose the whole machine, and a single cards is easier (and cheaper) to replace. I have built my own electronics for the spindle and the coolant. I don't bother with a charge pump, so I still have spare outputs. I am waiting for a PWM card to run my inverter to control the speed from Mach3 - s Christmas present, hopefully

The thing I meant about the "dir" pin is - something - and it would appear to be your spindle output - is switching the "dir" pin of your axis as well. Test the "dir" pin and see if it is switching to +5 or 0v for the faulty move. It seems to be that switching on your spindle also switches or cancels your axis "dir" pin. Whe it gets the oppsoite comand it is then reset and works OK again. On a printer port pin 16 was the "initialise" signal. Whether this should interfere with the data lines, I do not know , but it seems to be that yours does.

Sorry I didn't realise that F5 switched the spindle, I do all mine from the mouse screen, and if the fault occurs when you use the mouse, it can't be your system hotkeys.
Not me driving the engine - I'm better looking.

Offline SimonD

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Re: Odd Startup Behavior
« Reply #9 on: December 16, 2007, 04:07:40 PM »
Don't get me wrong I think the StepMaster is a good card. But I agree the single cards are better. The 3axis one I have has the breakout built in which I think is where my problems start.
I too have built my own electronics for the spindle and coolant but am not totally happy with them which is why I am planning on going the charge pump route.

Thanks for your replies.
Simon