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Gerald_D
Registered
Username: Gerald_d
Post Number: 753
Registered: 11-2005
| | Posted on Monday, January 22, 2007 - 07:12 pm: | 
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If the the acceleration factor in Mach3 (motor tuning) is set too high, then it is completely normal for a motor to get overloaded and lose steps during the accel. stage of the movement. But then it will do it also when runnning only one axis....
Does your power supply perhaps lose voltage when it has to push 4 motors? Is there a regulator in your power supply that starts to clip/oscillate? The transformer is maybe too small? (should be around 300VA - looks much smaller in the photo). You say it is a standard power supply in your company - can you give each axis its own supply as a test? |
DocTanner
Registered
Username: Doctanner
Post Number: 17
Registered: 11-2006
| | Posted on Monday, January 22, 2007 - 09:30 pm: |
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Fabrica,
Is your computer fast enough? An underpowered computer would cause these same symptoms.
DocTanner |
Gerald_D
Registered
Username: Gerald_d
Post Number: 755
Registered: 11-2005
| | Posted on Monday, January 22, 2007 - 09:45 pm: |
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Very true Doc. Thanks. (How is your animal behaving itself?)
At this point I don't think it is an interference issue.
Extremely unlikely that the PMDX has anything to do with it....it is actually a pretty dumb device. MUCH more likely the PC driving the PMDX. |
fabrica
Registered
Username: Daya
Post Number: 221
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 01:26 am: |
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My settings for acceleration for x and Y axis is 500 mm/sec and for Z it is given as 1500 mm/sec.
The transformer which we are using was just lying around in our factory. It has a wattage of around 1500 Watts. This is putting out 48 V AC into the PMDX 135-8020 power preparation module. The powder comes out of the prower prep module after getting multiplied by a factor of 1.66.
If everything fails I will provide each axis a individual power supply.
The computer is a Dual core running at 2.8 Ghz with 1 GB RAM.
Could any software on the PC be interfearing with the signals. |
DocTanner
Registered
Username: Doctanner
Post Number: 19
Registered: 11-2006
| | Posted on Tuesday, January 23, 2007 - 01:44 am: |
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Fabrica,
Your computer is more than adequate. There are a lot of things that interfere with Mach3. It wants fulls control There is a file on Mach's website http://www.machsupport.com/optimisation%20XP.txt Backup your system first!!! |
fabrica
Registered
Username: Daya
Post Number: 222
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 02:09 am: |
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Doc, Up from 4.00 am trying to figure out this problem.
Since you pointed me towards the problems that I may have on the computer side. Below given are my observations while setting up mach 3.
The mach version I use is Version R2.0.015. Does this have a special driver for PMDX cards. I could not find the PMDX option in the drop down list while configuring the mach 3. On the device manager list I found the PMDX card listed as a pulse generator. |
fabrica
Registered
Username: Daya
Post Number: 223
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 02:20 am: |
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Does the PMDX card have a driver for it. It is definitly not plug and play. |
fabrica
Registered
Username: Daya
Post Number: 224
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 02:48 am: |
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Gerald, As you very well know the motors that I use are Oriental PK296A1A-SG3.6. On the motor it mentions a stepping rate of 0.5 degrees per pulse. Is this after considering the Gearing ratio.
I understand that normal steppers operate at 1.8 deg/pulse.
Microstepping is done at the Gecko drives is it? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 756
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 05:36 am: |
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It is very early here...have to got to work. The PMDX card has zero intelligience, zero memory - it cannot even talk to a PC to tell that is plug&play. A PC could never detect its ID. It cannot use a driver (too stupid), so there is no driver for it. You could connect the printer cale direct to the geckos (some people do this) but the PMDX makes the wiring easier - that is why it is called a "parallel breakout card".
The 0.5 degrees is after considering the gear ratio. |
fabrica
Registered
Username: Daya
Post Number: 225
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 07:10 am: |
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Gerald, In the morning cleaned up the computer as per the intructions given in the link provided by doc.
We feel that their is slight improvement in the smoothness of the motors.
Now when engaging the router on a samlla cutting programme (without tool) the motors are moving smoothly when cutting straight lines. When cutting arcs all three motors on x and Y axis stagger and move.
Gerald, on the motor tuning and setup screen you get two inputs called step puls (1-5) and dir pulse. What is the normal velocity you use for all axis. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 757
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 08:53 am: |
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Cutting speeds are mostly in the range 1800 to 3600 mm/min. Sign letters in MDF typically 2400 mm/min. Just cutting a lot of straight shallow grooves at 7200 mm/min. |
fabrica
Registered
Username: Daya
Post Number: 226
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 09:11 am: |
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Gerald now the only problem (for the moment) that I am facing is that while only one axis is moving (cutting on a straight line) the movement is ok and smooth. When two or more axis are moving (cutting arcs and circles)the whole gantry is jerking.
Gerald, on the motor tuning and setup screen you get two inputs called step puls (1-5) and dir pulse. Whet do these two inputs mean. |
fabrica
Registered
Username: Daya
Post Number: 227
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 09:12 am: |
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I have just started to move the bulky transformer and place it outside the control box. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 760
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 09:29 am: |
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On Saturday afternoon I asked if the problem was speed related and you said it was not....
It is known on ShopBots, and also on the MechMate, that the gantries and cars start to resonate at higher speeds when cutting arcs and circles. This problem is definitely speed related.
From the mechanical side it is critical that the V-rollers sit very correctly and firmly on the rails. The Y-car must have the spring roller (M130100) on the side away from the motor.
But, the above problem does not cause the motors to lose/gain steps. You are telling me that you are gaining/losing steps?? We have to be very clear about this.
If you cut around a full circle, and you have the erratic problem, does the cutter finish at the starting point, or is there an error?
error = electrical problem
no error = mechanical problem |
Gerald_D
Registered
Username: Gerald_d
Post Number: 761
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 09:40 am: |
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"on the motor tuning and setup screen you get two inputs called step puls (1-5) and dir pulse. Whet do these two inputs mean." I think it is a way of lengthening the pulses coming from the PC - have never used them so I don't know. |
fabrica
Registered
Username: Daya
Post Number: 228
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 04:48 pm: |
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On saturday afternoon Gerald we were working on the jogging mode. We ran the machine fast and slow but the problems that we encountered happened while running fast as well as slow. That is why I informed you that speeds are not linked to the problems encountered.
We checked the V rollers and also the bearing fitted to the opposite side of motor mount on Y car. They were ok.
To get a conformation on weather this was mechanical or electrical related problem we disengaged the Pinions from the racks and ran a circle cutting programme. All three motors are jerking while turning. We are now very sure that this is a electically related problem.
We also cut a full circle with motors engaged to racks although the movenet of the gantry is Jerky the circle was ok it ended up at the same place.
We are still working. |
DocTanner
Registered
Username: Doctanner
Post Number: 20
Registered: 11-2006
| | Posted on Tuesday, January 23, 2007 - 05:38 pm: |
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Trouble Shooting:
Disengage motors by removing the springs
Gantry should go from one end to the other with a firm push
Y-car should do the same
Z-axis should remain stationary with motor spring removed.
All v-wheels should remain in full contact during all of this. Movement should be very smooth.
With springs replaced, Move the gantry. It should take a firm push to move.
Reverse movement of the gantry. There should be no "slack" when going from one direction to the other.
Slack indicated a loose pinion gear
Do the same for each axis.
Use pin connector for every connection to breakout board and Gecko
If you don't have a quality crimping tool for pin connectors, then it's best to solder then cover with heat shrink tubes.
Motor wiring: From Gecko to motor:
Pin 1 Ground
Pin 2 Power <---possible culprit "I'm using 70 volts from toroidal transformer"
Pin 3 Coil A = PK296A1A black
Pin 4 Coil A~ = PK296A1A green yellow Do Not Connect- Insulate from any contact
Pin 5 Coil B = PK296A1A red white Do Not Connect- Insulate from any contact
Pin 6 Coil B~ = PK296A1A blue
Pin 7 Not Connected
The PMDW-122 board is recommended, but a simple breakout board will work for trouble shooting
Pin 8 Direction - From Breakout board
Pin 9 Step Pulse - From Breakout board
Pin 10 "Common" 5 volts <---- from computer or breakout board (correctly jumpered PMDX-122)
Pin 11 resistor 8.2K 1/4 watt resistor
PIN 12 other end of resistor
If everything checks out, then go to www.machsupport.com/videos.htm They have some great tutorials.
Hope it helps. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 762
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 06:26 pm: |
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"we disengaged the Pinions from the racks and ran a circle cutting programme. All three motors are jerking while turning. We are now very sure that this is a electically related problem.
" Well done! That is a very helpful diagnosis. The problem sure is electrical or software.
Because the circle completes fully and there are no errors in position, I believe that interference is not the problem.
It looks like Mach3 and your PC are having problems giving evenly and correctly spaced pulses to the steppers.
I hope that you have the Mach kernel speed set to 25kHz. Config > Ports & Pins. I have heard that you shouldn't set it higher unless you have a very good reason.
May I suggest that you take this problem to the Mach support forums? |
fabrica
Registered
Username: Daya
Post Number: 229
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 06:39 pm: |
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Gerald, Problem sorted out. I do know that in the process of sorting out my problems I blew your fuse on sevaral occasions.
My computer guy whom I recruited to the design jobs on Artcam had accidently enabled the Auto limit overide button on the settings page (press Alt6 on main menu). He has done this to overcome a problem at some point of our testing stage and forgoton to switch it back to the disabled stage.
I feel that when we are overiding limits on mach 3 the programme goes on to a safe mode and due to this does not obey many of the commands that go through a G code based sequence of events (programme). This is why the machine behaved well while running on the Joging mode and not on a programme mode. |
fabrica
Registered
Username: Daya
Post Number: 230
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 06:50 pm: |
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Just to prove a point I thought of uploading the above given pic. These cuts were made before the exact prob was identified and also at the time of these cuts the motors were very gerky in their movements. Can the pictures prove any of these misbehavoir. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 763
Registered: 11-2005
| | Posted on Tuesday, January 23, 2007 - 07:36 pm: |
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Very glad to hear that you found the problem!!
Also very sorry to hear that I give the impression that I have blown fuses. I know that I have an abrupt manner, but please don't read it as angry. This project is squeezed in between other projects and I mostly don't have time to talk about the weather and cricket  |
fabrica
Registered
Username: Daya
Post Number: 231
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 08:00 pm: |
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Gerald, I know that you would be one of the happiest guys to learn that I have overcome this tricky issue.
It is now 11.10 pm local time. I was waiting for a response from you before I hit the deck.
Talking about blowing fuses, Don't take it up too personally. The remark was made just to inject some houmuor into a very formal discussion on this thread and theirby to make it a bit more lively.
I also wish to mention here on this thread that if not for the strict dicipline that you have enforced on this forum this disucuusin board would have been loaded with a lot of unwanted crap.
Hats off to all you guys in this forum who made my life easier in the process of making this machine into a working beast, specially you Gerald.
My story does not end here. If I do not encounter anymore serious issues in the next couple of days I would stop all activities on the machine, dismantle all components and start to give everything a good finsh. Once this is done I will post a lot of pics for you guys. By doing so if I could make life somewhat easier for the guys who will be building Mechmates in the future, I would be the happiest guy under the sun. |
fabrica
Registered
Username: Daya
Post Number: 232
Registered: 10-2006
| | Posted on Tuesday, January 23, 2007 - 08:06 pm: |
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Thanks Doc for your efforts very much appriciated. |
Stephen Hull
Registered
Username: Oliver2257
Post Number: 6
Registered: 01-2007
| | Posted on Tuesday, January 23, 2007 - 11:55 pm: |
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fabrica,
Following your progress has been, for me, like an exciting story, unfolding, wondering what was going to happen next. And what a great ending.
Also your input of questions and answers has been extremely helpful. I have parts coming in the next few weeks.
Stephen |
DocTanner
Registered
Username: Doctanner
Post Number: 21
Registered: 11-2006
| | Posted on Wednesday, January 24, 2007 - 12:43 am: |
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Congratulations!!!!!!!!!
Does this mean you get the serial number 000001SR? I reckon I need to apply for 000001US lol It is quite impressive to see one of these things running for the first time. Several problems I encountered were solved by following your log. Now the difficult part begins: the software. |
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