Philips, Grundig, Millplus Information Collaboration

[jaideepshinh]

Dear Members,

Attached are the photos of the bios from my machine. This is for anyone who may need this in future. I have missed out a photo of EXM Slot 5 but values are same as EXM Slot 4. Will upload another photo of that later on.

Best regards

Jaideep

 

[Nerv]

I'll save you some time and effort, you cannot swap out that motherboard for a replacement, period. Even if it is the same type. Only upgrades possible on the CPU side is to processor itself. Take care of that board.

 

[vetalkp]

Good afternoon. My EXM-HD board does not work, the HDD failed and the board stopped working after the HDD was replaced.
Does anyone have experience repairing this board?

 

[Milan1989]

You can’t connect a hard drive that’s running Dos to a newer windows computer or it will rewrite the boot sector/ MBR. If you connect to another computer, it needs to be an OS besides windows like Mac osx or Linux or it needs to be a Dos computer. I have successfully added files to correct corrupted files by plugging it into a Mac, and then dragging the files and overwriting the old files. as far as duplication goes, I would never use software duplication. It’s always better to get a reliable ide capable hardware duplicator that does bit for bit copies. I think there is a way to correct the master boot record in Dos but you’ll have to go to one of the Dos forums and ask around. I don’t remember exactly what was recommended.

Thanks Markp for your input, problem wasn't with MBR, but with hard drive itself, i sent it to repair shop and they replaced faulty electronic and it works, im able to start up machine but now i have a different problem.

When trying to reference X axis i get an error X04 max following error too large and the machine goes in in emergency stop (when machine approaches to reference point or limit switch) , and sometimes when starting machine it gives me error I310 card1 sercos fehler
so far i swapped ddc2 cards between axis, and input/output boards but still can't figure it out, i'm suspecting heidenhain glass scales.
if anybody has experience with this any help would be appreciated.

 

[Milan1989]

Good afternoon. My EXM-HD board does not work, the HDD failed and the board stopped working after the HDD was replaced.
Does anyone have experience repairing this board?

Hi Vetalkp, if you are from europe you should try contacting RGB elektronika, unis group or similar company that offers repair services i don't recommend trying to repair it your self. fastest solution would be to buy replacement board .

 

[Nerv]

Thanks Markp for your input, problem wasn't with MBR, but with hard drive itself, i sent it to repair shop and they replaced faulty electronic and it works, im able to start up machine but now i have a different problem.

When trying to reference X axis i get an error X04 max following error too large and the machine goes in in emergency stop (when machine approaches to reference point or limit switch) , and sometimes when starting machine it gives me error I310 card1 sercos fehler
so far i swapped ddc2 cards between axis, and input/output boards but still can't figure it out, i'm suspecting heidenhain glass scales.
if anybody has experience with this any help would be appreciated.

Go into your axis diagnosis screen and watch the scale and servo encoder values while jogging axis. This is by far the easiest way to determine if the scale is functioning properly. Sometimes a following error is due to a dragging servo brake as well.

Now that you have that hard disk functioning again, duplicate that drive to a fresh HDD. The DDC2 Cards have those very poor orange connectors at the top that have the circuits for the relays that control the servo brakes. If the pins get loose (and they do!) you can have everything work fine but the servo brake will not disengage although the control thinks it did. This instantly produces a following error, or an overcurrent error. Also, stress caused from heat can cause components on the DDC2 boards to break pins on the safety relays. The DDC2 boards are unbelievably expensive to replace (If you can find any) so be careful handling them. This is true of all components of that control at this point, especially the PC board as I said earlier.

 

[Nerv]

Good afternoon. My EXM-HD board does not work, the HDD failed and the board stopped working after the HDD was replaced.
Does anyone have experience repairing this board?

I'm skeptical the board itself is to blame. Does the HDD function fine when accessed in another PC? I do all of these functions from my HDD duplicator and it does not affect the HDD boot ability when put back into the VME control.

 

[Milan1989]

Go into your axis diagnosis screen and watch the scale and servo encoder values while jogging axis. This is by far the easiest way to determine if the scale is functioning properly. Sometimes a following error is due to a dragging servo brake as well.

Now that you have that hard disk functioning again, duplicate that drive to a fresh HDD. The DDC2 Cards have those very poor orange connectors at the top that have the circuits for the relays that control the servo brakes. If the pins get loose (and they do!) you can have everything work fine but the servo brake will not disengage although the control thinks it did. This instantly produces a following error, or an overcurrent error. Also, stress caused from heat can cause components on the DDC2 boards to break pins on the safety relays. The DDC2 boards are unbelievably expensive to replace (If you can find any) so be careful handling them. This is true of all components of that control at this point, especially the PC board as I said earlier.

Now that you mentioned there is an over current or missing motor current error in one specific situation. when error X04 appeared first time i entered in machine constants and saved the parameters without changing it so the control would reset, then when i try to move x axis in opposite direction, to move it away from reference point it immediately gives x68 missing motor current (translated from german manual).

DDC2 card should be functional since i swapped them between XY and C axis and the error remains on x axis , i will check voltage on brakes to see if it has 24v or not.

Company that repaired my hard drive made a copy of it just in case something happens

 

[Nerv]

DDC2 card should be functional since i swapped them between XY and C axis and the error remains on x axis ,

Well perhaps the card itself seems okay when cool, but this problem can be affected by temperature. The orange connector that plugs into the DDC card is very likely a part of your problem. It can be the little contacts inside, or the wire connection has become loose. These connectors are the single worst component on the entire machine.

 

[Milan1989]

Well perhaps the card itself seems okay when cool, but this problem can be affected by temperature. The orange connector that plugs into the DDC card is very likely a part of your problem. It can be the little contacts inside, or the wire connection has become loose. These connectors are the single worst component on the entire machine.

I have checked everything you suggested and couldn't find whats wrong, then i decided to remove way covers from Z and X axis to see what is happening. as far as i can tell my machine don't have limit and homing switches but instead uses Heidenhain LS486 glass scale to reference x axis, as far as i can tell machine goes over scale reference point and doesn't stop there but continues until it hits fixed stop, in that moment it gives X04 error, so i removed glass scale and sent it to repair shop for testing.
while waiting for response from the repairman , i will also check all cables from DDC2 card to motor,encoder and glass scales.

 

[Nerv]

I have checked everything you suggested and couldn't find whats wrong, then i decided to remove way covers from Z and X axis to see what is happening...

What did the axis diagnosis screen show for scale feedback? Usually the machines do have secondary sensors for end of travel feedback, but this may not be always true. On my older 532 mill they are actual mechanical limit switches that are located in a completely different area than the scale. I would search around for them or review your schematic to see if it has them. If it were sticking or damaged that may be contributing to your problem. Pulling the scales would not have been my first move because now you have to reset all your machine constants for the tool changer and similar.

 

[Milan1989]

What did the axis diagnosis screen show for scale feedback? Usually the machines do have secondary sensors for end of travel feedback, but this may not be always true. On my older 532 mill they are actual mechanical limit switches that are located in a completely different area than the scale. I would search around for them or review your schematic to see if it has them. If it were sticking or damaged that may be contributing to your problem. Pulling the scales would not have been my first move because now you have to reset all your machine constants for the tool changer and similar.

My machine is in German and i couldn't understand everything so i followed my instinct.
this machine definitely don't have mechanical switches i followed every cable to see where they go and didn't find switches and i reviewed schematic and couldn't find it.
In the end problem was with linear scales, there was a problem with signals coming from reading head, machine wasn't able to register reference mark , but the guy that was inspecting it was able to adjust everything.
Scale was installed back in machine and now is able to reference x axis and no more error X04.
now all that remains is error I310.

 

[jaideepshinh]

Hi Milan,

I faced the same issue as you have a few months ago- the Z track feedback from my scale reader wasn't coming and my machine would hit the hard stops and trip. I had a spare reader head and changed it, and machine worked well thereafter. We diagnosed it within about 30-40 mins and got the machine running in a few hours.

Please note you need to re-calibrate your machine kinematics if its a 5 axis machine. DMG machines with scales do not have limit switches to the best of my knowledge. Not one of mine use limit switches- all are on scale reference marks and software limits. They do have proximities to check if you are referencing in the wrong direction/beyond the scale marker.

I'll try to do some homework on the I310 alarm and get back to you.
best regards
Jaideep

 

[vetalkp]

dmu50evo error C 64. What could be.

 

[stematic]

Hello! I have DMU125P with MILLPLUS V320. I need to reset C axis position (0-360) but I can't use G93 C3=1 (from V400)
is there any machine constant to do this? thanks

 

[jaideepshinh]

Hi Stematic, Were you able to figure out the issue? When you say you need to reset C axis position, does that mean go back to machine reference?

 

[jaideepshinh]

I'm facing a peculiar problem on my DMU125P (V410 control). The Y axis has been showing a "Y+30" alarm which is described as settling time overflow. This basically means the axis is not exceeding the maximum permissible error, but isn't coming to a halt fast enough. On dialing the machine, the axis is overshooting the commanded position, and then trying to come back to the desired position. This occurs more prominently when moving the axis in one direction than in the other. Has anyone experienced this problem so far?
Works carried out so far in an attempt to solve this issue:
1. Changed the Y axis ball screw, end bearings and coupling
2. Interchanged DDC2 card with B/C axis card.
3. Interchanged Axis output of X and Y (Changed Parameter 3100 to 2 and 3200 to 1, and changed motor, scale and motor encoder feedback connections)
4. Tried changing Position control Gain (1500->2000 or 1000), Velocity control Gain (6000->8000 or 4000), Velocity integral time constant (100->150, 70), Velocity Feedforward gain- (100%->120%, 70%), Acceleration feedforward gain (32000 -> 40000, 25000)
5. Reassembled ball screw to check for misalignment or incorrect loads on the locknuts

None of the above have helped. The intensity of the problem or reaction time changes but the problem inherently remains. The axis moves very freely on its rails and it doesn't appear to be a case of non uniform load.

Does anyone know how to access the pitch error compensation on this control? Or how the axes were tuned originally at the time of manufacture?

Any inputs would be most appreciated.

Next actions:
1. Swap motor in Y axis with another machine
2. Call DMG tech in for a service visit.

 

[Nerv]

I notice your profile doesn't show your location. Where are you from?

Don't change the axis gain settings. Change all the axis setting to original machine constants.

Move the axis so upon stopping it stops against a dial indicator and film it so you can watch it in slow motion, this may help you visualize what is going on physically and help determine if this is physical or electrical in nature. You said you did this and it's overshooting the position but obviously it wasn't giving this error before and it is now, so something has changed and the axis constants do not relate to this problem. Also film the screen on the axis diagnosis screen and watch the scale values there to see if this helps. I don't have this particular machine in my shop, does it have a direct drive on this axis? If so, what type of coupling is used to connect the servo to the ball screw? If it belt with torque limiters I would be inspecting those parts to see if they are causing this, though the encoder feedback when compared to the scale feedback would show this as well.

When you rotate the ball screw by hand (watch with dial) is there any backlash? When you stop turning and then try to turn it again is there any appreciable about of "static friction" or any cogging feel? From your description it sounds like this is purely mechanical, especially because you electrically isolated the drive side of this issue. Put everything back to original with the machine constants and axis and make certain this isn't backlash related.

I do know how to access pitch error tables but I don't know how that relates to this issue. The original machine constants will reflect the original tune of the machine.

Are you sure your X and Y Servos on this machine aren't the same type? On many Deckel Maho machines they are. I doubt it is the servo itself, it would give other alarms besides this if it was. How is the brake on that servo? Manually actuate the brake and try spinning the servo to see if the bearings are okay and the brake isn't dragging.

Feel free to PM me to discuss more if needed. I can help you with this issue for sure, there are more things it can be and I can take you through them.

Regards,

Dave @ Nerv

 

[jaideepshinh]

Dear Dave,

Thank you for your in depth post. I very much appreciate your taking time out to help out with my issue!

Videos showing the issue:
Axis overshoot -

Do not look at the movement values- we are just touching the axis jog button and it not in step mode. The same overshoot happens in the reverse direction as well, but less somehow. It is more visible at higher feed rates.
PWM scale diagnosis -

I am located in Bangalore, India.

On the points you have mentioned:
1. I have restored all parameters back to the original values, with the exception of 3283- Settling time for Y axis (original was 150, now it is 250). If i reduce this to the original value the axis becomes inoperable (every stop results in Y+30 Settling time overflow)
2. I am unable to pin point where the issue is. I have made videos of the machine when being dialed- the axis overshoots by about 40-50 microns, then reverses, and then goes forward (basically oscillates until it achieves the correct position) and stops at the exact commanded position. Something like a spring.
3. We have used a PWM21 unit- the scale feedback and control feedback match, and the PWM picks up the axis oscillation as we are seeing on the dial. However, the oscillation is within the movement error limits, which is why the control does not throw a positioning error alarm, and does not show the values on the main page. In the axes diagnosis we are able to see a negative lag value at the time we are stopping the axis.
4.The axis is direct drive- There is a spider coupling between the motor and the ball screw. I have installed a new coupling as we suspected the coupling might have an issue or the polyurethane spider may have lost its rigidity.
5. I will recheck on the backlash to be sure- we checked the axis in a more crude way- Push and pull with the machine kept in emergency stop. The axis deviation before ball screw and end bearing change was about 20 microns. After ball screw change, this deviation is 1 micron. Ball screw is brand new purchased from DMG.
6. The axis movement feels perfect by hand. We moved the axis without ball screw and it moves super smooth. The ball screw rotates perfectly, although when coupled with the axis, it is tight in our opinion because of the new seals. I am contemplating installing the old screw again to check if this problem gets any better. The old screw was rough, but is holding its preload well. The backlash was because of busted drive side bearings, and before change the ball screw assembly was rotating very rough which we assumed was the cause of this issue.
7. X and Y servomotors are the same. I intend on interchanging and seeing if this is the issue.

I have called DMG for a service visit but that would happen next week. I am not sure if the team here can handle this problem, as their answer over phone is to get the machine laser calibrated as the compensation values of the old screw are messing up this screw movement, which I know is not the case. The compensation values are only active after machine referencing, whereas I am facing this overshoot even before referencing is done.

Any inputs or guidance on the way forward would be most appreciated.

 

[Nerv]

6. The axis movement feels perfect by hand. We moved the axis without ball screw and it moves super smooth. The ball screw rotates perfectly, although when coupled with the axis, it is tight in our opinion because of the new seals.

This is where I would be tempted to dig further. Make sure the ballscrew and nut is properly aligned with the ways/castings as well. That drag you are feeling might be enough to cause the polyurethane spider to compress enough to start an oscillation like you are seeing. Swapping the old Ballscrew assembly back now that you know it was the end bearings that were causing most of the backlash may be the fastest solution, that test would certainly yield helpful information for your diagnosis. It is likely the end bearings were the initial cause of the problem and now it's something different but still relating to the unit mechanically.

7. X and Y servomotors are the same. I intend on interchanging and seeing if this is the issue.

Do this as soon as possible to rule this out. It is very quick and easy to do and if this winds up showing the issue lies with the Servo any other time spent before doing this test will wind up been wasted.

Dave @ Nerv