[turbods1300]

We have a '94 Arrow 750 with CT control and it has been working fine until today. We turned the power switch on the back of the cabinet to fire it up for the first time today and roughly 5-10 seconds later, before the CRT monitor displays any bootup sequence or information, the spindle turns on to max power without warning or reason! We have a 6k rpm spindle and the SpindAx display showed values over 11,000! I'm assuming this was RPM and if it was...Yikes! We promptly shut off the power as soon as we realized this was happening. We repeated the sequence and threw the power switch on again after waiting roughly a minute. We monitored the SpindAx display this time as we powered it up. First it showed the text "CAL" for a few seconds and then it switched to "RDY". Within a second or two of the "RDY" being displayed, the spindle would power up and freewheel until we cut the power again. What is going on?

There was only one thing that was different during the initial startup today versus any other day we've used the machine. There was a DB25 cable connected from the RS232 port on the machine's cabinet to our PC that sends it the programs. The cable was connected to both the VMC and the PC and the PC was on with Cimco Editor running - we had forgotten to shut off the computer after we were done sending programs to the mill over the weekend...so the PC was still on with Cimco app open when we first threw the power switch on the mill today. Is that the culprit and if so, what is the remedy? Google hasn't provided me with much information on this and I didn't find anything similar to this searching the forums here on CNCZone. Any help you can provide would be greatly appreciated. We weren't able to obtain any information off of the CRT monitor because it wasn't and normally isn't displaying information yet at the time when the spindle turned on. Oh, last detail...the E-STOP button was depressed when the spindle engages so it is not paying attention to that or the spindle stop buttons, likely due to the machine's computer not being booted up yet.

Please let me know if there is any additional information I can provide which would be helpful in diagnosing this issue and thanks again for your help.

[turbods1300]

Does anyone have any thoughts on this? Thanks in advance.

[pete from TN]

turbo...
I am not sure how much help this is but I experienced the same exact thing several times. When I was having this issue I was also having power supply problems and it seemed to happen just as you described. As far as the spindax readout don't worry too much. The spindles on these machines have 6k rpm spindle speeds but the Spindle MOTOR speed is with a 2-1 ratio. SO when your spindle is churning out 6k RPM your motor is whipping along at 12k believe it or not. It is certainly unsettling when you flick the switch and turn on the machine and the spindle suddenly ramps up to max RPM without warning or reason. Did you try to run it without the RS232 plugged in to see if that is the problem? Also you might try to push in the Estop button upon startup before you flick the main disconnect. As I recall that did not seem to matter on my machine.

Also how long have you had this machine? Are you running it on a phase converter? I had all sorts of problems with my machine and was actually forced to do a retrofit on it to LinuxCNC control recently and now it is behaving nicely altho I am still working on the toolchanger controls yet. I can use the machine and make parts now and everything but no toolchanger until I get it configured in the software. Good luck with your machine man. If you cannot get it sorted I would recommend contacting Rob Varney at Mag and see if he knows what is going on. Peace

Pete