Cutting properly after debugging - Milwaukee, WI

[smreish]

My only concern is the VFD is in the same box. A recommendation is to have the VFD OUTSIDE or in another enclosure. I know others have had success with the spindle drive in the same box...I did not. Bad EMF can be a bugger to troubleshoot.

Otherwise, looks like your in good shape. Be certain to route your mains power to the contactor away from everything else if you can if you plan on keepin the drives on the bottom.

Most of the control cabinets have this arrangement....
DIN RAIL and contactor row on bottom.
Drives in the middle
Power supply and PMDX on top for signal and power type separation.

Your box is large enough to go with mostly any configuration that you like. So just be mindful of to long of parallel runs of power and signal together to minimize cross talk on lines.

an example of my box is here : http://www.mechmate.com/forums/showt...?t=460&page=15
Sean

[bradm]

Tuan, in the e-stop enclosure, I would expect to see one set of N.O. contacts on each of the outer (yellow and green) buttons, and TWO sets of N.C. contacts on the big red stop button.

[riesvantwisk]

I second that with Sean (remove the VFD), additionally I would put the power supply on the top left and the BOB on the top right. THis way you can also have a more room for your Gecko's on your cooling plate and you will have more room around your BoB.

Ries

[KenC]

I go with Ries & Sean removing the VFD from box.

I personally will mount the Din rail on the back of the door.

[tnarch]

Thank you for all your suggestions. With regards to the VFD, is there any kind of shielding I can do to keep it all in the same box? As for the layout of the components, I see that the popular arrangement Sean referred to seem to work best taking into consideration all the cabling (w/o the VFD).

I managed to get Mach3 to move one X-axis motor . It was a great feeling of accomplishment to see motor action with no smoke coming out anywhere This exercise yielded two questions.

1) I am using Gecko 201x with these motors. The 201x has 10 DIP switches and I configured it to output 4.4 amps. After running the road runner sample 2 times, the gecko was many times hotter than the motor. I am switching to the 8 wire motors as Mike R suggested from post 8. The drives will be sitting on a heat sink with a fan. Is there anything else I could do to reduce the heat?

2) The picture shows that the power supply is connected directly to the disconnect switch and not the contactor. What exactly is the role of the contactor? I had to buy a this 35 amp contactor because they were out of the 20 amp when i ordered. Should the current of the power supply and contactor match exactly?

Lastly, any tip for running cables through the chains?

[bradm]

Tuan, the goal of shielding the VFD will fight with the goal of keeping it cool with airflow. In general, VFDs will be happier if they aren't in a box - if you read the manual it will probably give you some guidelines on how much free air space should be around it.

So I agree with Sean, Ries, and Ken: Don't put it in the box. I bet that once you embrace this, you'll come up with a really elegant place to put it and way to wire it.

[riesvantwisk]

Tuan,

if you mean with the contactor 'The big relay' where all currents go through to the motors and fans... Then the role is to cut-off the cabinet when the e-stop safety button is pressed. The E-stop buttons are routed with the 110V/220V volt through one of the relays contractors. If that circuit is broken (you pressed a button) then the machine is turned off.
Second, in some countries you have to have a method in place that removes all power from the machine and cabinet when the cabinet door is open. The poweron and power off buttons are also partof the contractor circuit.

Does that clarify?

Ries

[KenC]

Other advantage of having the VFD out of the box is that you can see what ever that is display on the LCD screen, I always set the Amperage display so that I know how much current is drawn at any time so as to vary my feed rate or spindle speed accordingly. Don't worry about dust getting into the box, if you run a vaccuum dust collector dust won't git that far...

[tnarch]

thanks guys for all the comments.

i ran into a issue. what does it mean when the magnetic contactor doesn't hold latched position? when i pushes the on button, the light goes on and i hear the contactor latches. however, when i release the on button, the light goes off and the contactor releases. any help is much appreciated.

[bradm]

Tuan, it means that you've wired it wrong. You usually use one of the aux contacts to maintain the power to the contactor after the start button is released.

So, you should run from the power source to one side normally-closed off button, then from the other side of that button to both one side of the on switch, and in parallel to one side of a normally-open aux contact on the contactor. From the other side of the on switch and the other side of the NO aux contact to one side of the contactor coil, and from the other side of the contactor coil back to neutral. The on button pulls the contactor in, and the the aux contact holds it there regardless of what the on button does. The off button breaks the circuit, no matter what.

[tnarch]

Hello All

Almost there! Everything is wired. I attempted to do the first cut but the spindle/vfd got in the way. With the power on for motor and vfd, and Mach3 Reset button is solid green, the Reset flashes red as soon as I press Run on the vfd.

I wired the e-stop for main power and BOB using the same 7 core cable. In the attached image, big red line is the cable. 2 small red lines are used for power estop. 2 small blue lines are for BOB estop. The yellow are unused currently. The BOB estop circuit is disconnected in the picture and replaced with the factory jumper. This configuration will NOT trigger the error i mentioned above.

What should I do differently?

Third picture shows my little celebration for making dust.

[Kobus_Joubert]

Working on a MM is THIRSTY work

[Alan_c]

In General Config, try unchecking the "Use Watchdogs" check box - see if that makes a difference.

[tnarch]

Kobus, i'm with you

Alan, I looked into Gen Config, Use Watchdogs was already unchecked. I checked it just to test it out. same result either way.

anyone else has any suggestion? thanks.

[Alan_c]

What is your "debounce" value, try something like 2000.

[smreish]

Similar problem happened to me....you can read the drama in thread in trouble shooting section.

http://www.mechmate.com/forums/showthread.php?t=1859

Things I changed in my set up:
- debounce pushed up higher...2000 or above (push it to something like 8000 and see if this helps....then scale back until it repeats again)
- added an isolation transformer for the spindle (but it had other problems too)
- turn off watchdogs
- added isolation transformer to spindle (this fixed the steppers from moving when spindle on - different problem than your seeing)
- added isolation relays to the inputs of the PMDX so inputs would see transients from pushbutton wiring on gantry)

[javeria]

look at this from Matt's thread

http://www.mechmate.com/forums/showt...1&postcount=67

A torroidal ferrite on the output line also helps and I have used it successfully additionally you can try adding a .01uF ceramic cap across the terminals of the Estop on the BOB,

what I have done on most of my machines is use a 24V DC control line across for all external control switches and then use PC817 optoisolators to interface them with the BOB

also look at this

http://www.powerqualityanddrives.com/emi_rfi/

hope this helps

RGDS
Irfan

[tnarch]

thanks everyone. i will try all of your suggestions when i get to the shop tomorrow.

[danilom]

I posted this somewhere else but here is it again, about internal EMC capacitor filter in my VFD (Control Techniques) . I don't know its function but it triggered estop on friends machine so I kept it disabled on mine, and everything is running fine 6+ months. On mine it was a small plastic tongue besides power connectors which should be pulled out.

picture from VFD manual:

[tnarch]

increased debounce values mitigated the error! thank you alan and sean!!!

[Surfcnc]

Tuan you have omitted an important detail - the debounce number you used !!

Regards
Ross

[tnarch]

Ross

I started up at 8000 like Sean suggested and incrementally decreased it by 500. When I hit 2000 the error came back. Then I "fine tune" it by stepping at 100. 2300 was the magic number. But I set it at 2600 for some buffer.

[Surfcnc]

Thanks Tuan, it is always good to get some feedback on a solution that worked.

Ross

[tnarch]

hi all

getting some really weird action

in testing the debounce values further, i found that if the z car gets too close to the x-rails and near the x motors, the EStop is triggering. this is intermittent and doesn't always happen along both xrails. in one instant, it reversed my z motor! thank goodness it was only 1 inch and no harm done. at first i thought i might have typed Z-1.0, but i double checked and it was Z1.0.

In full disclosure, I am running Mach3 on a laptop while waiting for my lcd touchscreen. Ferrite rings are also on their way. Beside switching to desktop and adding ferrite rings, anything else i should be checking for? (i also will be trying some of the other suggestions from earlier.)

Another BUG, a big one, moving in the positive direction for all axes. I've noticed after having the system on for awhile the following occurs:

1) I can only jog in the negative direction. jogging any axis in the positive direction will only produce motor hums and no movement (Mach3 DRO are increasing.). If there is movement, motors are miss stepping for sure. Motors are ungeared and are tuned to basic specs from Gear Speed Step Frequency excel.

2) If there's movement in the positive direction, jogging in the x will torque the gantry as if only one x motor is turning or the two x motors are turning opposite (if even possible)

The way I've debugged this problem thus far is to shut off the motors and drives. Wait a few minutes. Turn them back on. Open and run the first few lines of the road runner Gcode sample. Back to "normal".

Any thoughts or pointers will be much appreciated as always!

T

[javeria]

Tuan,

Lower you velocity on motor tuning window in Mach, check if you have good ground/earth everywhere. check the grounding thread http://www.mechmate.com/forums/showthread.php?t=4

RGDS
Irfan

[bradm]

Tuan, did you ever switch those motors, or are you still on the 6.8mh inductance units? Are your geckos still running very warm?

When the system is running, is it easy or difficult to cause a motor stall if you (carefully!) push back against the gantry while it's moving? It should be scary difficult to stop the gantry; ideally the springs will let the pinions go before the motors stall. If this isn't the case, you aren't getting enough power from your motors.

Earlier in this thread, the discussions about the motor power calculations were based on using a 3-1 gear-down, but you appear to have direct drive at the moment, so I suspect you have insufficient torque.

Slowing your velocity, and particularly your accelerations settings may make the gantry move, but it will still be very prone to problems once you start cutting - think
about the kind of force a hand-held router can throw back at you.

So, your first problem to solve is: get your electronics and motors running without excessive heating. This may involve switching out the motors, decreasing the amperage, and/or increasing the voltage. Switching the motors is the best.

Your second problem to solve is getting enough mechanical advantage: switch the motors to some with gearboxes, or add belt drive transmissions. Either solution is fine.

The fastest way home is an expensive set of OM geared motors. Next best is 8 wire motors plus building transmissions.

[tnarch]

Irfran, thanks for the link. I will reread the thread to make sure I'm running my ground proper.

Brad, I did switch motor. I'm using these with Bipolar Parallel wiring. The geckos are not warm at all. These 201x has DIP switch to set their current output. I set them at 5.8. Should I go higher?

I haven't tested pushing against the gantry while it's moving. That does sound scary. Can you explain a bit more by what you mean "...ideally the springs will let the pinions go before the motors stall."

There is current no gearing and there isn't $$$ in the budget for expensive OM. I was hoping to get the machine to acceptable working order and cut transmissions with it.

As for torque and motor tuning, in one experiment, I pushed the motor velocity to 600 in/min and acceleration to 8/in/sec/sec. The gantry was moving smoothly and fast. It was like music to my ears However, this also fell ill to the BUG I described in my last post.

[bradm]

Ah, Tuan, that's good news so far. I'll focus elsewhere then.

The springs that hold the pull the motor mount plates to hold the pinions in the rack are designed as a failsafe mechanism - they will let the pinion slip out of the rack in extreme conditions like the gantry or toolhead crashing into an immovable object.

However, given that you've already gotten strong motion and you're on a reasonable motor, that takes us back to why it's shutting down, and then working again after a rest period. That still feels like heat to me, and not noise.

Here's two other thoughts: When the system is in it's failure mode and will only
jog in a negative direction, can you move the gantry or Y car by hand? If yes, then something is funny in the power stage - you aren't getting holding torque from the Geckos/Motors. If no, then the issue is in the control stage - either the computer or the BOB is getting unhappy.

How is the BOB being powered? Is it possible that the power supply to the BOB is unstable when warm? In particular, is there a voltage regulator that is running warm?

In Bipolar Parallel, you should potentially be able to push higher amperage through those motors. You could also try switching to Bipolar half-coil.

[tnarch]

Hi Brad

I tested the spring action you described by running the gantry at very slow speed against the stop blocks. The pinions slipped.

I tested for heat like this:
I isolated the motors for each axis and tested a thousand lines of code for each. Geckos 201x Standby is turned OFF so full current is always flowing to the motors. Motors were tuned to run at 600 in/sec an 8 in/sec/sec. I also changed to Dir/Step pulse setting in Motor Tuning to 5 microsecond. Per axis, I ran the code twice. The motors are warmer than normal after the first run. But the second run did not show any symptoms of the BUG. This led me to believe it is not heat. I should mention that the gcode for each axis is specific only to that axis. For example, the X axis gcode was:

F300
G1 X0
X1
X2.56
X67.32
......

I then loaded roadrunner into Mach3. The problem came back at the 6th and 7th line. On the 6th line, the Z did not travel to 0.2. On the 7th line, the X and Y did not move. From here on, the X and Y moved just fine. The Z continued to be a problem. I had moved the spindle to 2 inches above the bed, and then zeroed it out before starting the program. By the time the gcode is done, the spindle is touching the bed. Yikes!

As for holding torque, it's present when the system is in failure mode. BOB is power by a 5VDC from the power supply. No heat present any where BOB or power supply after the exercise I just described above.

After all this, I have two questions:

1) Is is possible that there's a loss of signal and/or power through the length of the cables? They are 16awg. The longest run to the Z is 25 feet.

2) I read somewhere in a post related to the PMDX that the Geckos should be grounded to the box through their neutral power line. Can anyone shed some light on grounding the Geckos if that's required?

I'm running out of ideas and running low on patience as I've been trouble shooting this for the past 2-3 weeks. Help?!?!?!

[Gerald D]

Tuan, I havn't looked at your full history....
Have you tried other PC's and another printer cable?