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Message |
    
fabrica
Registered
Username: Daya
Post Number: 183
Registered: 10-2006
| | Posted on Tuesday, January 16, 2007 - 09:31 am: | 
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Ok, I will do the required modification. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 718
Registered: 11-2005
| | Posted on Tuesday, January 16, 2007 - 10:39 am: |
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Screw head A (8mm) is supposed to be a countersunk because there is a risk that it can touch the angle iron rail. Head B (10mm) is above the rail.
There is a secial trick to hold screw A while adjusting the nut for tension. The tip of the screw (other side, away from head) is slotted with a hacksaw and then a screwdriver can hold the screw from the "outside".
If you have enough space for the screw heads, then don't change anything. |
fabrica
Registered
Username: Daya
Post Number: 190
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 02:30 pm: |
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The wiring is done and for the last three hours we have been playing around with the mach3 software get the settings correct.
Maybe we still have not got the pins and other things configured properly. When we try to jog with the sofware the motors do not move. No voltage is developed at the outputs of the steppers drivers. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 725
Registered: 11-2005
| | Posted on Thursday, January 18, 2007 - 02:41 pm: |
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I think it took me 3 days.......
I started on the kitchen table with one motor and one gecko - after that I built the gantries and cars.
A big problem for me was to understand what the E-stop does and how to "reset" the Mach main screen. Nothing will move while the reset button on the bottom left of the screen is flashing red - it must be only green. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 726
Registered: 11-2005
| | Posted on Thursday, January 18, 2007 - 02:51 pm: |
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To see if Mach is working, you do not need the Gecko's and the steppers. You can just look at the PMDX board. There are LED's that will flash where the gecko wires are connected, when the step/direction pulses are received correctly.
The PMDX looks like a discotech when everything is working right. |
fabrica
Registered
Username: Daya
Post Number: 191
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 05:53 pm: |
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Gerald, The last posting which I did under this tread has got lost. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 728
Registered: 11-2005
| | Posted on Thursday, January 18, 2007 - 06:26 pm: |
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Your previous post was at 2:30pm - there is no record of another post from you in between. Look at your "post numbers" which are stored in the database.
(I have just made a test and deleted post 727 of mine - this new post then becomes 728. So, this afternoon my post numbers jump from 726 to 728 if a post is "lost") |
fabrica
Registered
Username: Daya
Post Number: 192
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 07:09 pm: |
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Ok Gerald maybe I made a mistake by during the process of posting.
This is what i wanted to inform you in the earlier post.
" Gerald Finally I got the motors to move (of course with racks detached from the pinions). What i did to overcome the situ was to switch the jumper settings on JP2. From the original pin connections of 2 to 3 I changed to 1 to 2. This made the PMDX card LED's to light up and the motors to move.
By doing this I have disabled the E-stops, Fault and charge pump circuits. After doing this change I never expected the E-stop to work. But it still did work. What could be the reason for this?
Another reason why I did this change was because I suspected (after reading your earlier mail) that the e-stop settings are a tricky issue. Once I sort out the other matters I could get back to this problem later. The charge pump was also enabled through mach 3 settings.
After changing jumper settings all 4 motors started to turn, other that one motor fixed to X axis (A axis, slave of X).
At the driver point I changed the wire connections (switched the wires connected to non working driver to to the driver which was working) and the non working motor started to work. We could suspect two things. Either the stepper driver is playing up or the Output circuit of the PMDX card which connects the faulty driver board is not working. At this point we called it a day and wound up operatins since it was 8.00 pm in the night.
One more thing which I observed in the suspected stepper driver unit was the the LED in that was glowing much more brightly than the other drivers which were working normally.
Gerald Can a stepper drive be repaired if it is faulty?. Anyway I have one spare driver board in stock. |
Brian_B
Registered
Username: Allegheny
Post Number: 31
Registered: 07-2006
| | Posted on Thursday, January 18, 2007 - 07:13 pm: |
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fabrica,
The Gecko website has a nice "Stepper Motor Basics" page that will walk you through the theory and hookup. Go to: http://www.geckodrive.com/photos/Step_motor_basics.pdf
There are many similar pages available online as well. Another is:
http://www.rmsmotion.com/resources/step_basics_v1_0.pdf
Brian |
fabrica
Registered
Username: Daya
Post Number: 193
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 07:28 pm: |
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Brian, Thanks for your input. But how does the info provided by these links relate the issues that I have raised in my earleir mail.
The first issue which I raised was when I disabled the E-Stop (through jumper settings) to get the motors to turn how come the E-stop is still working.
The second issue was the problems that I am encountering with the Gecko drivers (only suspected not yet convicted). |
Gerald_D
Registered
Username: Gerald_d
Post Number: 730
Registered: 11-2005
| | Posted on Thursday, January 18, 2007 - 07:52 pm: |
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WELL DONE! You achieved in one day what took me about 3 days 
In Config > Ports & Pins > Input Signals scroll down to the line EStop and look in the column "Active Low" change from green to red, or vice versa to get the e-stop to work correctly.
The driver LED's are not equally bright - I don't think that this indicates a fault. (Gecko will replace a faulty driver for free, but you have to arrange the transport). I am guessing you have a Mach ports&pins error, so I suggest you swap motors at the PMDX to see what happens. |
fabrica
Registered
Username: Daya
Post Number: 195
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 08:08 pm: |
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Ok I will swap motors at the PMDX point to see where things have gone wrong and post you the results by tomorrow morning before you start work (we are 2.5 hrs ahead of you). Now it's almost 11.30 pm over here. It's time for me to hit the deck after very strenuous and ejoyable day's of work. |
fabrica
Registered
Username: Daya
Post Number: 197
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 06:30 am: |
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Checked the motors. It was was the driver which was faulty. Replaced the driver with new driver motor worked perfectly.From CNCZOne found a simiple way to check Gecko's. Info given below.
"Quick test. Disconnect the main connector, get a multimeter and set it to Ohms. Connect a probe to COMMON, then measure COMMON to STEP, then COMMON to DIRECTION. The reading you want to see is 1.2K give or take 5%. Get that and the drive is probably OK".
I followed the procedure and did the checking. Both readings were perfect. For the monet I will go ahead with the new Gecko and see what could be done with older unit later. |
fabrica
Registered
Username: Daya
Post Number: 198
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 06:33 am: |
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I have encountered two more problems today morning while setting up the machine.
One motor on the x drive is getting too heated. The other issue is that the Z axis motor is rotating only in one direction. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 732
Registered: 11-2005
| | Posted on Friday, January 19, 2007 - 06:48 am: |
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Hot motor: Check your resistor that you fitted to the Gecko. Do not trust your ability to read the colours on the resistor, use an ohm-meter to measure it. Measure all the resistors - if this one is different then that is the cause. If it is the same, then there is a setting under the cover of the gecko which must be checked.
Direction: On the PMDX there is a LED for each motor which shows the direction. Is this LED indicating the direction change correctly? (compare to the behaviour on the other motors) If it is, then check the wire connections between the PMDX and the gecko.
Strange gecko behaviour: nearly a year ago gecko had problems with bad connectors. They changed the supplier. Maybe you have one of these. The connector does not like to be removed many times from the gecko. |
fabrica
Registered
Username: Daya
Post Number: 199
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 07:45 am: |
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The problem with motor heating was sorted. After changing the drivers we had not inserted the resistor on to the new driver.
The problem with the Z axis motor still exists. It is only moving in one direction. When we try to move it in the other direction it only makes a noise but the shaft does not turn.
One more thing that I observed was that when pressing the e-stop button, the LED on the PMDX card which is situated just above the output connectors lights up. This is very unusual. |
fabrica
Registered
Username: Daya
Post Number: 200
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 07:49 am: |
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With regards to the lights on PMDX. For X,Y and A outputs the light tuns on when moving in one direction and does not light up when moving in the other direction. On the Z outputs the light turns on in one direction but is very faint. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 735
Registered: 11-2005
| | Posted on Friday, January 19, 2007 - 07:55 am: |
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Is the Z-motor still disconnected from the rack? What happens if you swap that motor's wires to another gecko?
Your e-stop logic, with PMDX jumpers and Mach ports and pins settings is still mixed up. I have little experience to fix this because ours worked right and then I left it alone for more than a year. The only thing I can suggest is to put the jumpers as per the drawing above, put a temporary wire across the e-stop contacts (like the pmdx was supplied - J6 across e-stop and GND), and then play with the Mach settings until it works correctly. When you put the motors against the racks, then you can put the E-stop switch in that jumper wire at J6. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 736
Registered: 11-2005
| | Posted on Friday, January 19, 2007 - 07:59 am: |
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Regarding the faint LED for the Z: Disconnect the wire below the LED (the one going to the Gecko) and see if it is still faint - maybe there is a short in that wire.... |
fabrica
Registered
Username: Daya
Post Number: 201
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 08:35 am: |
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The Z axis problem was sorted out, it had been a software issue (mach3).
I am starting to enjoy this Gerald. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 737
Registered: 11-2005
| | Posted on Friday, January 19, 2007 - 08:48 am: |
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Can I relax now?
Would you agree now that it would be good to have the 4 motors on the kitchen table at home first? Do this in parallel to the steel construction....
Now you can tell us your secret? I am sure you have already connected the motors to the racks and made the beast move.... |
fabrica
Registered
Username: Daya
Post Number: 202
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 10:04 am: |
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The machine is moving well without any problems. Setting up the home point (0,0) and the limits.
Please educate me on the the rate of accelaration that a normal mechmate should run at. We increased acceleration once and the gantry jumped off the rails. May be we should increase the tension of the springs further. We have kept it at the lowest point. |
fabrica
Registered
Username: Daya
Post Number: 203
Registered: 10-2006
| | Posted on Friday, January 19, 2007 - 10:08 am: |
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Hope I am not troubling you too much. Fully agreed on the kitchen table project.
Regarding your relaxation matter, no way. You have taught the wrong thing to a wrong guy. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 738
Registered: 11-2005
| | Posted on Friday, January 19, 2007 - 10:39 am: |
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Our MechMate has direct drive motors, so the settings may not apply to you....Our settings X & Y axes are 500 mm/sec/sec and Z axis is 1500 mm/sec/sec. Our machine is set rather slow and lazy. If we drop the acceleration down much more then we get round corners for square parts.
Mach is developing the Quantum to replace Mach3 and this will completely change those acceleration values again.
The correct accel. values are the ones that feel right for you.
I guess it sounded like the gantry had jumped, or that the teeth of the pinion had jumped out of the rack - but if you look closely you will see that the teeth are not jumping. That noise comes out of the stepper motor when it jumps internal steps. Believe it or not, it is actually harmless - nothing is damaged. You just get a very loud warning that your stepper has lost a step or four. (Some people say you must use servo motors because you don't know if your stepper has lost a step - believe me, you do know when a stepper loses a step. It is loud!)
Regarding the spring tension, you had better check it against a scale. The tension must be about 12kg. link |
fabrica
Registered
Username: Daya
Post Number: 205
Registered: 10-2006
| | Posted on Saturday, January 20, 2007 - 05:24 am: |
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Gerald, I found the reason why the gantry is climbing on to the x rails. The pionion wheel is slipping against the motor shaft. I have fixed only one grub screw.
Now I am fitting another one more screw on all motor shafts.
Can you advice me on setting the limits on the Z axis. |
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