[Mellbreak]

I was wondering if the switch that is on the back of some units switch the third pin (Red Wire) from the pot to pin 4 to enable the PWM to be controlled by the mach 4 software? Could it be that simple? Thanks Terry

I don't think so Terry. I seem to recall trying this myself and, also, a comment by kb0nly to the effect that he'd mapped out part of the PWM circuit on the board only to find it came to a dead end.

Terry (and anyone else), are you in a position tell me what the maximum RPM of your spindle motor is? Off load mine is 13200. I need this information to try and get a good fit between the Mach3 RPM number and actual spindle speed. I really just want to know if my figure is typical.

[Terrynf]

Have not checked on the speed but the motor is rated for 12,000 rpm. Also the forth pin I have been talking about go to MCU chip STC 12C5616AD Pin 15 Which is labeled P3.7/PCA0/PWM0. From the spec on the chip it would have to be programmed to use all of the functions. This pin also goes to pin 4 of an Optocoupler EL817 labeled (off) on the board and pin 1 of EL817 goes to pin 1 of the 4 pin connector for the PWM. If the MCU was not programed for that function that could be why it will not work.

Just a guess at this point but when pin 4 and pin 3 are connect the resistance is controlled by the MCU not the pot. When my JST connectors come I will try it out. Also the manual I have listed in an earlier post is for a Z-D system that uses the switch on the back of the box it also has all the setup info for Mach 3 to control the drill on/off and speed.

Do not try this unless you take all the responsibility for causing any damage to your system if it does not work.

[Mellbreak]

Well I've now got the software into a usable state. It's by no means perfect, but given the limitations and quirks of the original controller board, it doesn't do too bad a job. In reality I suspect any PWM controller using an unstabilized power supply and no motor speed feedback system would face many of the same difficulties.


A couple of pictures of the board for anyone who might be interested.


Attachment 262864 Attachment 262866


kb0nly's nifty automatic stop mod still works, which is nice, and my add on board requires no mods to either of the original controller boards.

I'm happy to post further details, including the software hex file, if anyone's interested.

Happy new year to all.


Bob

[Mellbreak]

Hi Terry,

Just tried your suggestion regarding pins 3 and 4 on my board - no luck I'm afraid. If yours works out differently, do let us all know. It would be a neat solution.

Bob

[canislupus]

how are you measuring the spindle speed?

sorry to resurrect a dead thread. I just got this machine.

best P

[Mellbreak]

Hi Canislupus,

At the moment, although I'm looking into this, there is no direct method of measuring spindle speed. In this case the board I built measures Mach3's PWM signal and adjusts the spindle motor speed accordingly. It's an imperfect solution, but so far nobody seems to have come up with a better method of providing software control with the JP-382A and JP-1482 boards. In practice it all seems to work well enough.

Regards,

Bob

[canislupus]

Do you think Id be able to implement your solution after changing the JP-382A to an Arduino Uno and a GRBL shield? This video is basically what im doing. the thing is, as of right now, I can isolate the two boards, in other words the arduino and steppers will be powered via the USB and this doesn't have to attach to the spindle chip at all. I checked this out by isolating the JP-1482 from the JP-382A and the spindle still works fine. Im not super familiar with electronics (I started this project to get some experience) but i think that the arduino has PWM stuff. Also, I plan to use universal g code uploader or something similar to run the steppers, so I really do have a lot of work ahead of me. Do you have any general tips? I can start a new thread and update it with progress if that would be more appropriate.

Thanks!

best P

[kb0nly]

Do you think Id be able to implement your solution after changing the JP-382A to an Arduino Uno and a GRBL shield? This video is basically what im doing. the thing is, as of right now, I can isolate the two boards, in other words the arduino and steppers will be powered via the USB and this doesn't have to attach to the spindle chip at all. I checked this out by isolating the JP-1482 from the JP-382A and the spindle still works fine. Im not super familiar with electronics (I started this project to get some experience) but i think that the arduino has PWM stuff. Also, I plan to use universal g code uploader or something similar to run the steppers, so I really do have a lot of work ahead of me. Do you have any general tips? I can start a new thread and update it with progress if that would be more appropriate.

Thanks!

best P

Sounds like you really took on a job there! I wouldnt know where to begin suggesting on that! I have very little Arduino experience. But i suspect as long as the Arduino can toggle the on and off like the original controller did there is no reason it couldn't. All it would take is an analog output from the Arduino to switch it.

[iBeta]

Hi Canislupus,

At the moment, although I'm looking into this, there is no direct method of measuring spindle speed. In this case the board I built measures Mach3's PWM signal and adjusts the spindle motor speed accordingly. It's an imperfect solution, but so far nobody seems to have come up with a better method of providing software control with the JP-382A and JP-1482 boards. In practice it all seems to work well enough.

Regards,

Bob

I know this is an old thread, but have just got the controller (ha, the E-Stop button was loose- the flimsy plastic threaded piece had bust). Can't find much info about these boards, except for here. The 3020 user manual stated turning up the rheostat too quickly risks burning out the board, at best just blowing a fuse. Thing is, the photos in the manual were of the old style (blue) controllers so maybe it was just a problem with those. These do seem reasonably well built I think.

Anyway, would it be possible to use the stepper board feedback signal to determine loading? It measures current through the 0.2R, which will be effected by spindle load.

Has anyone tried changing logic on the unused mcu pins and see if that has an effect on the manual/auto pwm operation? Would think that the controllers that have software control, would also have a manual alternative.