Need Help with a CALU Mirac

boots · Post by **boots** » Wed 21 Feb , 2007 16:56 pm

I know this rambles, I pieced this info together.

California University of Pennsylvania
Mirac
machine serial # U00158/1
dispatch date - July 2001
electronics serial # - OC00253657

"In order to try and get more “real estate” on the computer monitor, I attempted to increase the monitor resolution. However, the monitor resolution was not supported and left me with the inability to see anything. I contacted the University Computer Services to have them change the resolution back to its original setting. In the mean time, I connected a different monitor to the machine and ran it this way for a few days. Computer Services came to change the resolution back and had difficulty (due to their abilities and not anything with the machine) changing it back. After making a number of attempts that involved turning the machine on and off, they determined the computer part of the machine was now not operating. They thought that it was a computer power supply problem and attempted to replace it. In the process of doing so and testing it, the tech reported hearing a “pop” and was told not to work on the machine and to have the manufacturer service it. He turned off the machine power and the filtered power supply.

I wasn't present when the computer tech ran into the more troubling problems. I went in yesterday and checked some things out. From what I determined, all the fuses located in the machine (in the upper left hand corner) checked out as O.K. The external power supply had a blown 15A primary fuse (I'm not sure what the tech did, but it sounds like he caused some type of short). The secondary fuse was O.K. I did not have any other replacement fuses at the time. Later that day I purchased some. My plan is to replace the fuse in the external power supply and, with it disconnected from the machine, power it up. If all goes well, I plan to disconnected the power cable to the internal computer, reconnect the external power to the machine, and power up. If all goes well with this, connect the power cable to the internal computer and try powering up. Does this seem O.K. and reasonable to do since some type of short had to be present to fry the 15A primary fuse?

When I was putting things back together after the tech got done (he had unplugged the power cables to all the drives, motherboard, power supply, etc.), I noticed a two wire cable above the computer and wasn't sure where it was to be connected. It has the same connector as the computer power supply and has I think one red and one blue wire. Since we have two Miracs, I thought it would be easy to figure out by checking the other one - but it doesn't have that cable at all. What is it for?
Anyway, I did as I described below. All went well. The machine portion seems to be O.K. (I have not tried to connect it to a different computer yet). However, the computer portion still seems dead. I checked the power cable going to the computer power supply and it is outputting 240 V as it should. The computer power supply seems to be dead. I replaced it with one that came from the computer taken out of our Triac. I am not the one in charge of the lab and I have not taught in the lab in nearly 7 years so I don't know if the power supply was good or bad on it. To continue, when I power on the machine now with the replaced power supply, the CD ROM light does come on as it normally would when the system powers on, but nothing else - no monitor display (even with an external monitor connected), the CPU fan does not turn, and the power supply fan doesn't seem to be operating. When I check the output voltages of the computer power supply, they are basically at zero."

Any ideas or suggestions?

Steve · Post by **Steve** » Thu 22 Feb , 2007 9:24 am

It sounds like the PC power supply is no good.

If the machine is OK then you could run the machine with an external PC.

The only connection between the two is the RS 232 cable.

The best way to check things out is to leave the PC disconnected. Disconnect the RS 232 from the internal PC and thenget another PC from somewhere and load the software on that.

Then connect the machine to the new PC via the RS232 cable and see if it works.

I am not sure what version of software you have but think it is VR Milling 2 (as I visited CAL U to do some service about 12 months agao). If this is the case this should run even on XP.

If you can identify the control card in your machine it would help.

viewtopic.php?t=116

Post by **Denford Admin** » Thu 22 Feb , 2007 15:54 pm

It will be VR Turning if its a Mirac, download the latest version here:

http://www.website.denford.ltd.uk/suppo ... -downloads

To test on an external PC, you could unplug the RS232 from the PC (the one that goes to the Baldor control card) and lash it up to the new PC.

The internal PC and monitor could then be removed for repair (I would also recommend you check the VGA cable from the PC to the monitor as it could have been disturbed and broken or shorted internally)

boots · Post by **boots** » Thu 01 Mar , 2007 19:12 pm

I am not sure what card is the control card. There is a motion control
card that has a red LED display showing the number 8. There is only a
ribbon cable connecting to another card - there are no orange connector
blocks on it.

Our computer people replaced the internal computer with an external one.
I am able to get the machine powered up, can connect to it using VR
Turning, can home and jog the machine, but the tool turret will not
rotate. The toolpost drive in the back of the machine shows nothing
when the machine is powered up. No LED display.

When I first connected to the machine I was able to get the spindle to
turn on and off using the M codes in the jog window. After a few
minutes of doing this it doesn't work any more. The spindle drive is
showing that it is working (i.e. LED display is lit).

Any suggestions on what I should check/try?

Post by **Denford Admin** » Thu 01 Mar , 2007 22:56 pm

no lights on the toolpost motor certainly indicates a fuse gone.
if the spindle looks like its working but no rotation then this could be a fuse, emergency stop contacts faulty or guard interlock switch is not making.

you (or someone else) need to get hold of a multi meter and go round checking voltages (qualified electrician only!) to determine why there is no voltage to the toolpost drive or spindle motor

boots · Post by **boots** » Mon 05 Mar , 2007 20:51 pm

Connected external computer to Mirac, Tool Turret does not work.
- All fuses (F1 to F7) check out O.K.
- Spindle decided to work today.
- Turret still will not rotate.
- Toolpost drive shows zero (or nearly so) volts when machine is powered on.

Post by **Denford Admin** » Mon 05 Mar , 2007 22:26 pm

I wonder if the Emergency Stop relay is faulty / dirty or sticking contacts ?

With you saying that the spindle suddenly started working again ....
Both the spindle and the toolpost motor will be interlocked with e.stop somehow.

Will have to look through drawings tomorrow, but I'd take a closer look at the e.stop relay (think its a contactor on those machines).
See if its switching on and off OK from the e.stop button, and then check that voltages are getting through from one side to the other.
I remember earlier machines used a high current contactor for the emergency stop, to switch mains voltage (eg to the toolpost drive) as well as the low current e.stop signals. The low current signals may not make it through the contacts as they get older

boots · Post by **boots** » Tue 06 Mar , 2007 17:26 pm

I appreciate all the help you have been giving me. It is a shame all this happened because I decided to change the monitor resolution.

Anyway, I have some more information.

- I replaced F6 (fuse to turret).

- Checked voltage on output side of fuse and checks out to be around 230 V

- Checked voltage on output side of ESR (e-stop relay) going to turret. It shows around 230 V.

- Checked voltage across power input to turret drive again – shows only 19 V.

- Checked voltage from hot wire into turret drive to neutral coming into machine – shows around 230 V.

The last two items are interesting. It almost appears as the neutral connection from the turret drive has an open some place.

- When I check between the neutral connection on the turret drive and the jumper block where the neutrals are, there is no continuity.

- There is continuity between the neutral on the spindle drive back to the block. I would expect this since it is working.

- There is no continuity between the neutral on the spindle drive and turret drive.

Hope this helps.

boots · Post by **boots** » Wed 07 Mar , 2007 20:49 pm

I think I found the problem.
The neutral wire from the turret post drive to where it connects in the terminal block with the other neutrals was partially dislodged/loose. After retightening I was able to get the turret to work.
I will be doing a full test of the machine tomorrow.

Post by **Denford Admin** » Wed 07 Mar , 2007 23:47 pm

Great news - I blame vibration caused when machine was shipped over

PS - How do you like your new avatar ?

boots · Post by **boots** » Thu 22 Mar , 2007 14:11 pm

I haven't had much of a chance to do anything with the lathe for the last two weeks due to spring break and a bunch of work.

- What relay are your referring to that the e-stop controls? The solid state one labeled "ESR"? If so, what leads come from the e - stop?

- I don't think the switch is bad or the cause. The machine will not give any e-stop faults while the machine is powered up and stationary. It seems to only happen when I have the spindle on and there is enough of a vibration that an e-stop fault is generated. With the machine on I can basically shake the pedestal the e-stop is mounted on and it will not generate an e-stop fault.

Is there a wiring diagram you can send me or anything else? - I don't really want to have to tear into things too much to figure out what wire is what. I am afraid I will end up with an additional problem on top of the one(s) I already have.

boots · Post by **boots** » Thu 22 Mar , 2007 17:34 pm

I did some further testing. It doesn't appear to be a loose connection on the e-stop, but rather something to do with the spindle.

* If I power up and home the machine, I can jog the machine around all day and not get and e-stop message.
* I can shake the machine (much more than the spindle ever would) and never get an e-stop message.
* I created a little program that moved the machine through a variety of points in rapid traverse (and with the spindle off). I ran this program for a while and never got an e-stop message.
* Shortly after turning the spindle on in jog or in the program, I consistently get an e-stop message.

Post by **Denford Admin** » Thu 22 Mar , 2007 18:09 pm

I think it might be electrical noise on the emergency stop signal to the control - I have seen a similar thing in the USA before.

As I remember, I had to re-route the wiring for the Emergency Stop signal that goes to the Baldor control card. Not sure if your panel is the same layout, but I found the emergency stop signal went through the same big contactor that also supplied the spindle. I think over time, the contacts had worn, and the higher current supply to the spindle was creating noise that was picked up by the low current signal that fed back to the baldor control card.

Also, check that there is a capacitor fitted to the e.stop input, and that its securely fixed into the terminals.

A quick way to this is the problem out would be to wire a seperate push button into the e. stop input on the Baldor Control (be very careful now using the machine - as the emergency stop system is now compromised)

If you have the drawings for your machine, and a photo of the electrical cabinet, it would help me in finding a solution.

boots · Post by **boots** » Fri 23 Mar , 2007 21:35 pm

CalU MIRAC Photos.
I have some wiring diagrams here in Medina, not sure if there for this MIRAC, they could be faxed.

Post by **Denford Admin** » Fri 23 Mar , 2007 23:26 pm

That is a very similar layout to the problem I saw on a old Triac before.
The Emergency stop signal looks like it is going through the white Moeller ESR contactor - probably the thin red wire at the top, blue at the bottom. Either the red or the blue will go down to the green terminal block.
I think the problem is down to the fact that its using a big old contacts to switch the 5V signal to the control, and that these wires are located right next to the other ESR contacts which are switching the suppply to the spindle.

If I remember correctly, I had to wire up another smaller relay (a quality one with low voltage contacts) to be driven from the ESR contactor, then use this new relay to switch the 5V ESR feedback into the control. (this new relay wants to have a higher coil operating voltage - choose either 24VDC or 110VAC)

See attached "sketch" of what I think will fix the problem...
Please double check I have got the input voltages and relay wiring the correct way round as I have done this blind

Steve · Post by **Steve** » Sat 24 Mar , 2007 20:03 pm

The E-stop relay shown has a 24v coil so the diagram shown is not the solution.

I think the diagnosis you have that the problem is related to the spindle is correct.

The E-stop relay feeds the controller input with a Normally open signal that closes as the E-Stop is released.

It is possible that the low current input signal to the microprocessor is intermittant as the E-Stop relar is a power device and is designed for higher current signals.

Taking the signal to the microprocessor direct from the E-Stop button would be one solution. You could try fitting a new E-stop relay which would have newer and cleaner contacts.

The other option could be electrical noise from the spindle drive causing a false trigger to the E-Stop input.

If the spindle motor has demagnetised the spindle will run overspeed and at higher currents than when initially supplied. This can cause arcing on the brushes and create electrical noise.

1 I would suggesst you run the spindle at top speed and check the drive output and actual speed.

2 If the Motor is running at a higher speed than it should or the output voltage is higher than the motor rating then the motor should be replaced.

3 Try to link out the E-Stop input to the processor and try running the spindle then check to see if you still get the E-stop message. If not this proves it is either the E-stop relay of electrical noise.

4 If it does not trip wire a link over the same input but on the E-stop relay and run the spindle again. I the E-stop trip message comes up then the problem is in the wire routing of the E-stop signal or the spindle motor is generating noise.

5 Replaceing the E-Stop contactor would rule this out and leave only the motor or wire routing.

Hope this helps.

Post by **Denford Admin** » Sat 24 Mar , 2007 23:37 pm

The E-stop relay shown has a 24v coil so the diagram shown is not the solution

Perhaps the drawing was a bit misleading - I'm trying to show a new relay being driven from the contact that currently goes to the estop input - nothing will change with the wiring to the original 24v coil

ie, remove the thin ESTOP feedback wires on the old contactor, and use that contact (now spare) to energise / de-engergise a new relay with low voltage contacts

I'm sure this would be a better and longer lasting solution, than replacing the current ESR contactor with a new one, which may again develop the same problems

boots · Post by **boots** » Mon 26 Mar , 2007 14:17 pm

The diode you show going across the New Relay, Any particular value for 24v or 110v or 220v coil??

Post by **Denford Admin** » Mon 26 Mar , 2007 15:51 pm

If you are getting a relay with and AC coil, you will need to fit a Resistor/Capacitor (RC) suppressor
If you get a DC relay coil, then you can probably get one with a flyback diode already fitted - the part number normally has an extra D at the end of it. Otherwise its a normal 1n40 diode

Steve · Post by **Steve** » Tue 27 Mar , 2007 7:56 am

we normally use a 1N4003 or 1N4001.

I still think that you should try linking out the input to the Microprocessor first and see if the problem diassapears then do the same at the relay end.

If linking out the contact cures the problem at both ends then you have proved the relay contact is the problem.

If linking out at the Microprocessor end resolves but linling at the contactor does not then it is cable routing.

You should also check the spindle Motor.

Spindle demagnitisation was a major problem on older Boxford machines and caused random inputs to the microprocessor.

The problem was easily diagnosed as the spindle would overspeed.

Denford Software & Machines

Denford Software & Machines

Need Help with a CALU Mirac

Need Help with a CALU Mirac