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Machine specifics.

ClearPath Servos X4: CPM-SDSK-3441P-ELS
Power Supplies X2 w/ two servos per PS: ClearPath 350/500 Watt DC Power Supply IPC-5
Controller: MB3 with ESS and Mach4
VFD: Fu Ling DZB300B002.2LSA Input 3PH 220V 50/60Hz Output 3PH 0-200V 0-60Hz 2.2KW 10.0A
Spindle: 3kw 220v 10A 400Hz
EMI Filter on power into control cabinet: CW4L2-20A-S 115/250v 60/50HZ
Large farad on power line to Spindle unknown specs it came with my original Chinese setup
Farads on all control lines leaving cabinet to servos.
Power and control wiring for the servos are all Teknic supplied wires EXCEPT I used shielded outdoor rated CAT6 wiring to go from the MB3 to the circular aviation connectors to connect to the panel (maybe a foot long with farads on them0.
Spindle wiring is grounded. It wasn’t originally but I opened it up and grounded it then to the machine. Each moving part of the machine is grounded to the next piece of the machine until it gets to the machine frame. Machine is grounded to the building ground rod about 3 feet from machine. The control cabinet is grounded to the wiring ground which eventually is grounded to the same outside rod.


Z Axis issues

I am having issues with my Z axis and can’t figure it out. I’m posting this in multiple forums since I don’t know which component is causing the problem.

Z will stop responding to Mach4 randomly. There are no errors and Mach4 thinks it is moving and shows the coordinates changing on the DRO even though it is stuck.

Restarting everything, Mach4, ESS with MB3, computer and the machine won’t usually get it working again. I have to unplug the power plug for the Z servo from the power supply side and plug it back in. Unplugging from the servo end doesn’t do it most of the time. There are no LED errors flashing on the power supply when this happens.

When the Z servo stops responding the green light is still flashing on the servo and the Z axis cannot be moved manually as the servo is engaged. As soon as power is removed from the servo, I can push the axis up and down no problem.

I know VFDs are horrible for noise and sometimes this would happen after running a cut but there have been more and more times when I haven’t even starting cutting anything so the VFD has not been running the spindle.

I have been trying to troubleshoot this and looking at the MB3 LEDs there are some strange things going on.

I have the HLFB+ outputs from the servos connected to the MB3 even though I have not set anything up in Mach4 to use them. I’m honestly a bit confused as to what all I can do with them but I connected them so they would be ready for the time I do figure them out. I’ve noticed the LEDs for their inputs sometimes are all lit, other times only some are and generally when the Z is not working only one of the Y axis servos (I have a dual gantry servo setup) will be lit.

Today as I was getting info together to write this, I noticed only three of the HLFB+ inputs were lit but all axes were responding properly. I have the outputs set to ASG-Position, w/Measured Torque in the ClearPath tuning software.

Before when the Z would stop responding this would be frustrating, but it wasn’t hurting anything because it only happened when not running the spindle but now it is.

I’m cutting a large sign from HDU (sign foam) I could tell static was building up on the dust collector line and then the Z started getting lower and lower and starting cutting completely through the bottom of the sign into my spoil board, but Mach4 DRO showed it cutting the correct depth. It was colder outside with lower humidity which added to it.

I stopped and grounded the dust collector line which seems to have helped a little but on my next clearing toolpath with a smaller bit I could tell the Z height was still off from where it should have been the further into the tool path it went.

Does anyone have any suggestions as to what I can do to troubleshoot and eliminate this issue?

[joeavaerage]

Hi,
the only thing I can think of is that the MB3 has differential output for the motors whereas, if I'm not mistaken, the Clearpaths have single-ended inputs. My guess is that the
voltage swing of the MB3 differential motor output is marginal for the Clearpath input to recognise, sometimes it works and other times not.

Craig

[Formantjim]

Hi Chris I too use 4 Clearpath servos and used to use the ESS but switched to the ETH300 and use the HLFB for status only not ASG. I think that the HLFB signals are being generated and causing your issues. Try setting the HLFB to be status only and try again. Your Z axis sounds like it is loosing steps even though MACH 4 says its still moving. Since the MB3 has lights on it and not all of them are on that tells you instantly that something is causing the signals to be lost caused by too low a torque setting causing the HLFB to trigger.
Don't forget the Z axis servo sees a lot more force than the X or Y+A axes so its torque value will be different. It is carrying the weight of the spindle motor plus the axial load exerted on it as well as the radial by the X and Y servos.

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Thank you Craig and Formantjim. I really appreciate the help.

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A little update. I changed HLFB to just say the servo was ready for all four. Then I started cutting and realized I had set retraction way too high in my toolpath so I hit stop. When I came back and was ready to cut the updated file Z was not working again. This time I connected my laptop to the servo. The attached pictures are what it was showing me and the LED on top was yellow and slowly blinking. I wasn’t able to make the servo do anything from the Clearpath software until I unplugged the control cable this time, I did that first instead of power, and the servo came online with a green LED and I could move it again.

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An update to the update. Rebooted everything just in case and hit ref all and Z wasn’t moving again. Looked at the status LEDs and it was flashing green so it should have been good to go. Connected to my laptop and it showed it was connected and working and no faults. I tried jogging it with my pendant and it showed it getting those signals but still wasn’t moving.

Switched the cable with my X axis and it did the same thing on the X servo when I tried to move Z and Z servo was working and moving just fine when I told it to move the X axis.

So does this sound like maybe I just have a bad connection in my wiring?

[joeavaerage]

Hi,
it sounds increasingly like the Z axis motor outputs of your MB3 are nor adequate to drive the servo. It might be the MB3 or it might be the cable.

The motor outputs of the MB3 are differential, and I think are marginal (voltage swing) for the Clearpath. Try using some other NPN (non differential) outputs for the Z axis motors signals.

Craig

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HOPEFULLY this fixed it…..

I started playing with the connector at my cabinet and low and behold I could make it error and work that way. Took it out of the cabinet and started to remove the heat shrink covering all of the wires and the Z B+ wire wasn’t soldered in place anymore. Just the heat shrink around that pin was kind of keeping it connected. I resoldered it and reconnected everything and so far, so good. Fingers crossed.

I think I may want to change all of my circular aircraft connectors to some type of Molex like square connectors since the circulars are a major pain if anything goes wrong with them.

I’ll also probably change to the NPN connection on the MB3 as you suggested Craig.