Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: aahka on November 20, 2013, 09:34:00 AM
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This is my first attempt to start a new thread on this website. Please excuse my blundering if this a mistake.
I have been using a gecko G540 on a CNC router for over a year. We recently changed the table from a 4' x 4' to a 5' x 10' table. Then we started to experience recurring faults and E-stop reset messages on Mach3. Now we get a reset message occasionally when we move the Y axis. The X and Z axes work fine. The G540 red fault light comes on and the power green light goes off when movement stops along the Y axis as the result of an e-stop. We also experience an unusual phenomenon during a rapids command. When executing the following:
G00X10.8125Y78.5000Z0.2000
The router moves the correct distance along the x axis, but makes no movement along the y axis. The router also seems to drop at a slow rate along the z axis while moving in along the x axis.
We eliminated the limit switches as the problem by shorting them out during a trial run with no perceptible performance change.
Please provide any troubleshooting advice you can.
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When executing the following:
G00X10.8125Y78.5000Z0.2000
The router moves the correct distance along the x axis, but makes no movement along the y axis. The router also seems to drop at a slow rate along the z axis while moving in along the x axis.
It will all depend on your start position, for example if the Y is already at that point it will not move, if the Z is higher then it will lower.
We eliminated the limit switches as the problem by shorting them out during a trial run with no perceptible performance change.
Instead of shorting out the limit switches disable them in Mach. If they are shorted then noise could still be entering the system, if you disable them then Mach will not be looking at them at all so noise will be ignored. If disabling them helps then you need to cure the noise by shielding and properly grounding , possibly using a capacitor or as a last resort entering a Debounce Interval in General Config page.
Hood
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These are the preliminary lines of g-code in my program. When I reach line N200, the router is at the N190 coordinates of 0,0.
The router moves along the diagonal toward x10.8125y78.000 till Y=3.00 then all movement in the Y direction ceases and the router continues to move in the X direction to 10.8125
however, the DRO and toolpath on the Mach3 screen continues along the diagonal to Y=78.000.
I just seems like the stepper signal to the y motor & A slave motor ceases at about 3. This number will vary when the program is rerun between 10 & 11.
( CF-BM PROFILE X1 )
( File created: Thursday, November 14, 2013 - 10:41 PM)
( for Mach2/3 from Vectric )
( Material Size)
( X= 12.000, Y= 80.000, Z= 0.750)
()
(Toolpaths used in this file:)
(Profile 1)
(Tools used in this file: )
(1 = End Mill {0.25 inch})
N100G00G20G17G90G40G49G80
N110G70G91.1
N120T1M06
N130 (End Mill {0.25 inch})
N140G00G43Z0.8000H1
N150S20000M03
N160(Toolpath:- Profile 1)
N170()
N180G94
N190X0.0000Y0.0000F50.0
N200G00X10.8125Y78.5000Z0.2000
N210G1Z-0.3800F30.0
N220G1Y1.5000F50.0
N230G2X10.6875Y1.3750I-0.1250J0.0000
N240G1X8.3125
I appreciate your initial response. What do you think with this additional info?
I returned the limit switches to their original setup. The shorting them out was just a short term test to see if the problem was in the limit switch circuitry.
Jack (aahka)
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Ok that is a G0 move, it is possible your axis is stalling. Try reducing the Accel and Velocity (for Y at least) by 50% and see if it helps, if not attach your xml.
Hood
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I had previously reduced the acceleration, to no avail. I went into my shop and copied the xml file to a flash drive. There are numerous pages of text. How do I send it to you? Is there an email address so I can send it as an attachment? Is there a way to attach it to a post?
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You can attach the xml by using the additional options button on the reply page. You will have to make the name unique as the forum will only accept a file name once, so copy the xml to your desktop and rename it to aahka1.xml and attach.
Hood
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xml file is attached. Hope this works.
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Dont see too much wrong with the xml at first glance but please try again reducing the accel and velocity by 50% and see. That is the most common issue with steppers, they stall because they are just on the limit of working.
Also have you run the driver test to see what it looks like?
Hood
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Thanks. I'll try that when I go into my shop on Monday. I had also talked to a teck guy at Gekko who recommended the reduction in acceleration (my earlier reduction from 100 to 25 on all axis's). He also said that if that didn't work, try to place a 10,000 microfarad condenser in parallel with my 48 volt power supply. That condenser is on order. Do you think that will help?
aahka
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It depends on your power supply, if it is a basic transformer with a rectifier then you definitely require a capacitor to smooth the rectified AC.
Hood
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My initial velocity and acceleration setups were as follows:
X. 500 25
Y 500 25
Z 95 6
A 500 25
I did not vary the z-axis and lowered the velocity to 300 and acceleration to 10 on the remaining axes. The only thing that happened only was noticeably slower movement. The Y axis continued to trip an E stop at the termination of its movement. I lower velocities to 200 to 100 and acceleration to 5 and 1, respectively on all 3 motors ( X, Y & A) with no change in results except slower movement.
There is, however, one notable observational change. Movement of the X and Z directions were accompanied by a low steady hum similar to cat purring. Moment in the Y. direction sounded more like a variable growl, much louder and varying in frequency from low to high to low and resulting in an E stop whenever the Y movement stopped.
I ordered and changed out the parallel printer (db25) cable which I suspected might be faulty. No effect. The Capacitor has not yet arrived.
aahka
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Ok can you disable limits in Mach as I mentioned earlier so that we can see if that is where the E-Stop is coming from.
Hood
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How do I do that? I went through ports & pins, tried enable limit overload, no change. Can't seem to find a disable limits switch. I'm probably missing something basic, help please.
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You simply remove the green tick from them :)
Hood
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I switched off (disabled the limit switches) for all axis. The only Input Signal remaining enabled is the EStop with active low disabled. Still got an EStop when moving in the Y direction only when jogging motion stopped. I noticed that the only Output Signal enabled was the charge pump (port#1 & pin 1). I then disabled the Charge Pump and then jogged in all directions without tripping an estop after multiple attempts to do so. I then turned the Charge Pump back on (enabled) and rejogged in all directions. The Estop returned, again only on Y axis movement and only when jogging stops. Is it ok to operate with the charge pump disabled? Any other advice?
My 10,000 uf, 50 volt capacitor arrived today. I intend to connect it to my power supply interrupting a short between the positive to negative terminals. Is that ok or does it need a resistor in series with it?
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I have never used the chargepump on any of my machines. Its purpose was to stop windows toggling the I/O of the parallel port whilst starting. Over the years people have thought of it more of a safety feature in that if Mach crashed the chargepump would stop thus prohibiting the port being issued with signals, that however may not be the case, if Mach crashed it is just as valid a scenario that the chargepump would continue outputting.
Hood