Novaturn guard open problem, please help

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audio.fi
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Posts: 133
Joined: Wed 21 May , 2008 13:39 pm

Novaturn guard open problem, please help

Post by audio.fi » Sat 01 Jun , 2013 4:04 am

Hi,

I have been busy re-installing my Novamill which has been stood in an out building for about a year (sprayed with WD40 to protect it). It was working perfectly when last used. It has a smartstep board, and I am using fanucmd through dos on a 486 with dedicated rs232 ports on it for both the keyboard and control box.

The first thing I should mention it that I knocked the e-stop button going through the door to the workshop when bring it back in there, but having looked at it, I can see no damage other than it is now slightly loose. What I mean by this is that I took the lid off the trunking and although I cannot see the back of the front panel where it is fitted, I cannot see any damaged to the body of the actual switch and think I might have just broken the (presumably) threaded ring that holds it on.

Anyway, the problem is that the unit does not work properly now showing a "guard open" error message when I try to move the table in any direction. I did notice however, that the mechanical interlock for the guard only seems to work when the control box if off. When it is powered, the mechanical lock is pulled in by the solenoid. I was not sure if this was correct, so I un-plugged the header cable from the solenoid (after first powering it off and then back up again), and then mill started working. This lasted for only a few minutes though, and in that time I could jog at continuous and incremental modes. I also was able to run the motor up , but then, after changing the motor speed, the motor failed to run giving the "guard open" error again, so I have concluded that the solenoid was not the problem.

I can tell you that even with this error, I could then jog the machine, but only in incremental mode as it would not change to continuous mode after this problem appeared again.

I wasn't sure which section to post this in, so if it is in the wrong section, please put it where you think it should be, however I wrote here in the hopes that someone might know how to trace this problem. I could not find any circuit diagrams in the downloads section, but any circuit information would be a great help, or any help at all would be greatly appreciated.

I have decided to try to learn to write the programmes myself, and I am disappointed that this problem has appeared.

Thank you in advance.

Update :-

I have checked the contacts in the guard switch and both test out o.k. I also managed to remove the e-stop switch and the problem there was just that the plastic ring type nut had just jumped a few threads, so has been refitted. I checked the switch modules and both check out o.k. as well. I also changed the rs232 cable over to the one I have for my novaturn, but still no difference.

Can I check voltages going across the contacts on the guard switch ? If yes, what voltages should they be ? Would this voltage be reference to the mill chassis, and also, how important for the running is the earth wire within the trunking, as it is corroded (rusty), and tightens down onto the plastic of the trunking and is slightly loose. Please advise.

Update #2:-

I have found the wiring diagrams in the door of the control panel. If these would be of help I could scan them and upload them. Please let me know.
These are the documents that I have :-

Sheet 1 - Novamill Main Power Schematic NVM-01 C

Sheet 2 - Novamill Panel Layout NVM-02 G

Sheet 3 - Novamill Control Board Layout NVM-03 C

Sheet 4 - Novamill Standard I/O Unit Pins 1-25 NVM-04 C

Sheet 5 - Novamill Relay Wiring Details NVM-05 F

Sheet 6 - Novamill Spindle Drive Details NVM-06 C

Sheet 7 - Novamill Harting Connections NVM-07

Sheet 8 - Novamill Motor and Switch Wiring NVM-08 D

Sheet 9 - Novamill ATC Wiring NVM-09

Sheet 10 - Novamill E-Stop and Guard Interlock Circuit NVM=10

I have tried the unit again after giving the main big plug and socket a spray with servisol, but it made no difference, however, whilst trying it out, it started working for no reason, and the spindle worked at slow speed (I think it was preset to 100rpm), but as soon as I changed this to 1000rpm, the spindle went to start but as it spun up to speed, it stopped with the "quard open" error again. It seems to just be an intermittent fault, but the fact that it did the same thing just before i.e. the spindle stopped when I tried it at 1000rpm, might be a clue that it is current related perhaps ?

Any idea much appreciated.

Thanks.

audio.fi
CNC Expert
CNC Expert
Posts: 133
Joined: Wed 21 May , 2008 13:39 pm

Re: Novaturn guard open problem, please help

Post by audio.fi » Sun 02 Jun , 2013 8:36 am

Update (fixed)

For anyone in a similar situation, I managed to fix the problem.

I removed the smartstep version 3 top board and inspected it, and there was some corrosion on the multi-way header sockets at either end, and also some corrosion to some of the other larger soldered items on the board such as the yellow capacitors and the diodes. I carefully cleaned the areas with isopropyl alcohol and a new tooth brush, then re-soldered each pin on the headers and any other component that looked to have corroded soldering. I also sprayed servisol onto the headers, and re-fitted.

It now works perfectly.

Now onto my novaturn !

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