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CNC newby - motor setup question
« on: December 07, 2013, 09:34:14 AM »
Complete newby – would appreciate help and advice please .

I have a setup bought from CNC4U comprising their HG07 breakout board, 4 off CW5045 and 4 off 4Nm stepper motors. All wired up as per their datasheets and running via Mach3 on dedicated Windows XP Pro pc.
When I first bought the kit I had it running on my bench and everything appeared to work fine. I ran the Roadrunner example GCode program and the motors all moved and I’ve created and run a few very simple GCode programs which ran properly.
Now I’ve made up the motor mounts and fitted them to my machine the system does not seem to run so well and I don’t know why.

However I move the axes, whether under GCode program control or by jogging using the keyboard or joystick, the axes sometimes move at full speed and sometimes move very slowly indeed, and I have no control over what speed I’ll get. The speed doesn’t change whilst the motors are running, but from one jog or GCode move to another I often get a totally different speed. Sometimes it’s fast in one direction and slow in the other, other times fast in both directions or slow in both directions. Switching the spindle motor on or off seems to make no difference, and controlling the jog from keyboard or joystick or moving by Gcode makes no difference. I’m not in control of what speed I get but at least the DROs look like they’re counting either slow or fast at the right rate for the motor speed.

I’ve also noticed another strange thing, the main relay on the HG07 board sometimes clicks on and off at approx 1Hz, about 80% on and 20% off (indicated by a mimic led), and the motors turn with the relay on then stop completely when the main relay is off, and run when it’s on. However when this is happening and the motors are starting and stopping, the DROs on the Mach3 screen increment smoothly the whole time. I believe this means that Mach3 is sending out pulses constantly but the HG07 is not always interpreting them correctly.

I have not got as far as calibrating the axes – I realise I must, but until I’m in control of the speed there doesn’t seem much point. I’ve played about with motor and speed and acceleration graphs and they make a difference but do nothing to solve the problem. I have extended the step ad direction pulse widths in case this is a problem but it makes no difference to my problem.

The motors are not stalling, they have plenty of torque and everything is in the middle of each axes’ travel. Have asked CNC4U for some help and got a friendly reply but still not solved the problem. Can anyone shed some light on it for me please?

Many thanks,

Offline Hood

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Re: CNC newby - motor setup question
« Reply #1 on: December 07, 2013, 05:42:16 PM »
You would need to attach your xml and also the pdf or a link to documentation of your board. Pics or drawing of how you have the wiring connected would also be good.
Re: CNC newby - motor setup question
« Reply #2 on: December 08, 2013, 06:32:47 AM »
Thanks for the quick reply. I've been speaking to CNC4You again and they suggest the voltage regulator maybe shot - sure enough I've removed the card and the back is burnt. I'll change the chip / board and try again. Probably best to wait till I've done that before anyone else spends more time thinking about this for me. Thanks again, Mark