Need Help!- Can't get through homing

[ironworksdesign]

I have a Series I Boss 9 R2E4 mill and on boot up, it will take me to homing and when I execute it will take the spindle all the way up in Z and move the table about an inch to the right in X and then the drives kick out.

In jog mode, using the knob, X will run continuously in .1" mode and Z will only travel 2" total. Y seems to work correctly.

I'm at a loss as to where to go now. The voltages all seem to check out and all of the leds are correct except the green one signifying 5 volts on the BSP isn't lit. It reads 4.7v across the terminals though and I have the same on the back plane of the BSP.

I'll be grateful for any help!

[MrBoss8]

Does X travel at the normal slow speed when it shuts down when homing, or does the X move at a rapid move speed. If its a rapid for a short distance then shuts off the drives, you may have a defective X encoder (no lock, probably a bad light source, if it is an encoder problem). You can carefully remove the rear cover of your servomotor enough to see if the light source is working.

[ironworksdesign]

MrBoss8

Thanks for the diagnosis! This is exactly what its doing. It goes into rapid and then quits. The encoder took a hit when it was being unloaded and sustained damage to the connector. I was hoping that was as far as it went but I may have to send the encoder in to have it repaired.

[MrBoss8]

If there is no light source when you remove the encoder cover, make sure you are getting power to the lamp, which will confirm a burnt light source. Otherwise check your damaged connector. I have repaired a burnt light source myself by replacing it with a "grain o wheat" type mini bulb rated at 4v (I used 2 silicone diodes 1N4001 to reduce the voltage to the bulb since it was about 5.5v) after a couple tries it worked great, I used 3M weather-strip adhesive (gorilla snot) to hold the bulb in place. If your encoder does not lock after you do this, slightly change the position of the light source, then try homing again. Also observe the position of the original light source when removing it (and try to duplicate it). If you make detailed diagrams as you disassemble the unit you will be OK, and glad you took the time to do it.

[ironworksdesign]

I had the encoder open last night and the bulb is indeed dead. There is 4.7 volts at the terminals. A buddy of mine had bulbs so I repaired it today and now the homing proceeds by the Z going to the top and now the X will run all the way to the first limit switch and then it shuts the drives off. I'm back to the book to study up.

Where is home on this machine? Back left?

Many thanks for the help so far!!!

[ironworksdesign]

Well, here is the latest:
The Y encoder bulb was toast also so I replaced that one as well as the X. It now goes to the X home switch and stops. FIST log reads Can't Synch to Host, EAF not Active, No X Marker After Home Switch, E Stop, Log Dump to Host, Non-Volatile RAM Invalid.

Anybody have any suggestions?

[machintek]

All of your fist events are normal boot events EXCEPT the X axis marker pulse. This is a pulse that occurs once per revolution and tells the control when to start counting.
Switches are not inherently precision devices hence the use of the marker pulse.
Reboot the machine a few times to become familiar with what is normal in the control booting sequence.

George

[ironworksdesign]

Thanks George! Does that point to the X encoder as the trouble spot or does the pulse come out of the logic boards or somewhere else?

[machintek]

The source of a marker pulse is the encoder but plugs and cables must be good as well as the part of the control that needs to see it for it to be seen.

George

[MrBoss8]

Try this: Remove the axis servo drive belt cover. Do the home procedure, when that axis errors mark the pulley to belt relationship using a paint pen. (sometimes after a fault shutdown occurs a second home attempt will succeed, if this happen every time the following may help) Loosen the servomotor and reindex the timing pulley approx. 90 deg from the mark on the belt, tension the belt and home again. If it still does not work, try a couple more times keeping a drawing record on each belt adjustment. This hopefully will help.

Also you can check the distance to the end of ballscrew travel, Once the axis has limited and shutdown. Mark the ball screw in an appropriate place with a paint pen, then manually turn the ballscrew to the end of travel, record this in revolutions. This will probably be a fraction of a turn. if the switches have not been altered.

That is great if the bulb R&R really worked for you. I am glad to see that you got the FIST monitor hooked up, I've been recording output for ages and would be interested to see what the normal output from another machine during different runs would be, compared to my B8? But first things first.