Centroid Community CNC Support Forum

I have recently upgraded a Bridgeport EZ Trak to the Acorn CNC. I kept the 2 existing dc servo drives and bought 2 drivers for them. I made and added a dc stepper for the z axis driving the quill. All encoders are 1000ppr nominal. Software and system are great. I am however in the process of fine tuning the servo drives. I use a small 2" x 2" part with curves, sharp angles and straights as a test program. Only 1 z depth so it is really an xy test. Base speed is 40IPM and just simple countour type clearing (not adaptive). Program works great, smooth and steady.

However, when I try to turn up the feedrate to 110% or 120% the program starts cutting a few seconds and then very quickly gives a 327 Fault: Job Cancelled error. No other error messages but when I look in my cabinet all 3 of the drives have the "Drive Enable" signal inactive. I think this is something being generated by the Acorn controller but don't know how to track it down.

Any help or advise would be appreciated.

I found one 327 fault in the log file 11 seconds after Acorn started so I don't know what to think there. There are some spindle faults and quite a few axis faults. I'm guessing a drive is faulting and stopping your job.

Thanks Tom, the axis faults were me playing with the tuning to see if that was what was causing the fault. Adjusting the gain. Couple spindle faults are from re-starting the machine. If the drives fault out there is no reset for them other than power off and on (kind of a pain). If I power the machine back up before the voltage bleeds off the spindle vfd (30 seconds or so) I get a spindle fault. What throws me is shouldn't the controller give me a axis fault like you see along with the 327 fault?

I see only one 327 Fault in your log and it is right after reset had ben initiated. Keep in mind that a "327 Fault" simply indicates that a running job or MDI was cancelled because some other fault was detected such as a drive fault, spindle fault, limit fault etc..

If a fault occurs while a job or MDI is not running, no "327 Fault: job cancelled" message is displayed.

I do see spindle faults and drive faults etc.. so they all seem to be operating correctly

hi, you'd be further ahead by selling those old motors and drives on ebay and installing some modern axis motors and drives and you'd pick up more resolution at the same time.

Thanks to everyone's suggestions. I went into the acorn software and ran a simple program cutting a circle frame 6" diameter in air. Was able to run the drives up to 120IPM and they were smooth and perfect, I didn't even try any higher. This told me that there was nothing wrong with communication speed or processing speed etc.

I then went into the acorn and removed the "drive 1 okay" and the "drive 2 okay" signal. Ran my test program that gave the 327 fault and this time found out that both the x and y drives were faulting out at the same time at 50ipm. I guess the acorn doesn't know how to display an axis fault if both of them happen at once so it just says "327 Job Cancelled" and shuts off the enabled signals.

I turned the drive signals back on and now I understand the speed limitation of my system for larger smooth shapes vs small shapes with abrupt angle changes.

Thanks again.