Homing Error Problems...

[NylonAdmiral]

Hi all,
I have a Starmill and am running the latest version of VR Milling 2. Last night the mill was working fine as it has been for some time. This morning I went to run it again and found that the machine wouldn't home. After clicking "Home All" the Z coordinates (but not the X or Y) change but the machine does absolutely nothing. After a short length of time I get the error message:
"Machine Error: Axis did not home after 50.000 seconds"

I have tried a homeing several times and also occasionally get the error message:
"Major timeout problem sending []zz6[](mb)"

After reading through the forums I have tried the following things:

(The electrical box is powered up and I can see a seven segment display is illuminated which has been refered to in other threads).

I've checked the RS232 cable as best I can but the machine status says ready and I don't seem to have any problems when I actually connect to the machine so I think this is less likely as the problem.

I have checked the E-Stop but again the software registers when it is pressed and when it is released and short of pulling all the switch apart it isn't showing any obvious fault.

I have pressed the secret home button to try and jog the machine but it still wont move. I can't see any kind of debris that would be preventing anything from moving.

However, from reading through some of the forums I suspect a fuse could be at fault, however I am no electrician and the electric box looks a bit daunting! I have attached a picture showing the inside of the box. I have drawn a red box around what are obviously 3 fuses, all of which seem to be fine. Does anyone know if these are the fuses I should be checking or whether or not there are other fuses to be checked elsewhere?

Failing that can anyone think of what else might be causing this problem?

Any help would be greatly appreciated because I'm pretty stuck!

Thanks!

[NylonAdmiral]

Since posting I have spotted several more fuses. Two each on all but one of the boards across the bottom, and one more on a board directly to the left of what appears to be a unit that converts 240v down to 24v (pictured about mid way up on the right hand side with an illuminated green LED).

All of these fuses were fine.

[Martin]

Check the 4 fuses to the right of the fan.

[NylonAdmiral]

Thanks for your help. I have tested those four fuses too and all of them are fine. Do you perhaps have any other suggestions?

This is driving me crazy so and ideas would be great!

[bradders]

Hi there,

Can i ask, did you physically remove the 3 fuses on the back plane and check them out with an Electrical meter ?

[NylonAdmiral]

Hi,

The four fuses which are located "to the right of the fan" as described above were removed and checked for continuity with a multimeter. From memory they are labeled "F1, F2, F3, (unmarked)" from left to right. All seemed to be okay when I checked them. Are these the ones you mean?

Thanks for the help!

[bradders]

I meant those 3 you highlighted with the RED rectangle in the picture you posted.I just wanted to know if you had actually removed them and tested or left them in situ and put your meter across them. If you did this you may get a spurious reading. Its always best to take the fuses out of their holders and test that way.

[NylonAdmiral]

Thanks. I tested those ones in situ because I didn't want to disturb anything if I could help it. They also tested fine but I will try removing them and testing them again. I have to say though that the continuity seemed pretty good across them all.

[NylonAdmiral]

I've just been back and physically removed the fuses to test them. They all seem to be fine...

[Steve]

Hi,

The problem you describe where the machine does not home and that the axes do not jog even after using the secret home button indicates the problem you have is that the axes motors do not work.

This could be for several reasons. Can you repeat the procedure and do the secret home thing again.
Now when you press the jog keys the axes will not move but does the feedback on each axis change?

If the feedback changes it indicates the control card is sending out steps to the drives.

Now try and start the spindle. Does the spindle run? This would again indicate the controller is working.

The fact that the & segment display is lit on the control card indicates the logic power is present on the rack.

There is a seperate motor supply that energises the Axis drive cards in the rack. This supply will be broken by the E-stop and also fuse protected.

I suspect you need to follow that supply line and find out where you loose the supply.

I will see if I can find a schematic diagram and post here if I can.

[Steve]

I have attached the files I can find for the Starmill.

On the first page you can see the Axis drive transformer.

Check that you have 240V AC on the primary. This goes through F3 and the E Stop contactor. (Could be a faulty E-Stop contact thats the problem)

The second scanned sheet (No 6) shows the rack . Measure the output from the transformer in the terminals I have marked AC.

This is the output from the transformer before its rectified.

F1 and F2 on the rack are fuses for the stepper drives.

The drives transformer is shown at the right of this sheet mounted on the inside of the rack.

[NylonAdmiral]

Thank you so much for your help with this!


The problem you describe where the machine does not home and that the axes do not jog even after using the secret home button indicates the problem you have is that the axes motors do not work.

Right, I have repeated the procedure and done the secret home thing again. The following has happened:

Now when you press the jog keys the axes will not move but does the feedback on each axis change?
I have done the secret home thing and tried to jog the machine. I think I previously must have done the secret home thing after getting a time out error message. This time it was the first thing I did and it allowed me to jog the X and Y axis but not the Z. The feedback for the Z axis changes but nothing actually moves.

If the feedback changes it indicates the control card is sending out steps to the drives.

Now try and start the spindle. Does the spindle run? This would again indicate the controller is working.
The spindle also works after doing the secret home.

The fact that the & segment display is lit on the control card indicates the logic power is present on the rack.

There is a seperate motor supply that energises the Axis drive cards in the rack. This supply will be broken by the E-stop and also fuse protected.

So from your instructions it sounds like the control card is working, and surely if 2 out of 3 axis will jog it must rule out an E-stop problem? I will also go and measure the output from the transformer but does this not power all three axis? If this is the case then perhaps this can slso be ruled out as the problem.

It seems then that there could be a problem with whatever it is that actually governs the movement of the Z axis?

Using the diagrams you posted I will see if I can find anything obvious. From the above does this sound like a familiar problem to you though? Is there any way I can test whether its a failed drive card or Z axis motor or something like that?

Again, many thanks for your continued help!

[Steve]

Hi,

Sounds like we are getting somewhere!

The problem you have now is that the Z axis is not working.

When you try to home all the Z is the first to try and move so it times out.

The X Y and Z drives on the rack are identical so it is possible to switch a couple of the drives over and then see if the Z works and one of the others fails.

If the fault changes axes then it is the drive or a fuse on the rack.

If the fault remains on the Z then:

It would be possible to switch the motor wires from the Z and X motors again shown in the second sheet of the scan. This will prove whether the motor and wiring is at fault.

If with the motors switched you press the X jog the Z axis should move. If it does not there is a problem with the motor or wiring.

Note to test these use the secret home as if the axes have been switched the home switch would never be made.

Hope this helps

[NylonAdmiral]

OK, I switched the drive cards and the axis motor connections around and it seems that all the motors work. It also seems that the drive card is faulty because whenever I move it from Z to a different axis, that axis then stops working instead. I have removed both fuses from their holders on the car and tested them. They both are fine.

Where do I go from here? Can I buy a replacement drive card? Can I send this one away for repair? If so could you give me any idea how much either option might cost?

Thanks.

[Denford Admin]

Have a check of which drive it is - CD20 / SD20 or something like that
viewtopic.php?f=13&t=1151&hilit=cd20

Then either have a look on ebay, google or try Parker for a repair (from the above links)

[NylonAdmiral]

After contacting Parker they put me on to a company called Micromech (www.micromech.co.uk) who apparently repair these SD12 drive boards.

I've sent it away today, will post again when its returned, hopefully to report a working mill!