spindle speed control

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jacmarhal:
Hello. First post here, so be gentle. I have been using Mach3 on my Taig mill for quite some time. Everthing seems to work OK except the speed control. I have a DC motor being controlled by a KBIC control board. I also have a CNC4PC BOB feeding a Xylotex driver. I can turn the relay on the BOB for spindle on/off via Mach3 but I can not make the spindle turn. I believe I have everything set up in Mach to do this but Mach does not seem to output a signal to the BOB. I have pin 14 set for the spindle step. In MDI in Mach3 I enter M3S100 and I hear the relay on the BOB activate but the spindle does not rotate and pin 14 does not turn on (LED on BOB). I have followed the instructions on the manual for the CNC4PC BOB to the letter. I have gone through ports and pins, spindle setup, output pins everything I can think of, to no avail. I have even tried downloading a new version of Mach3 with no success. I am at my wits end and I need your help please.

jimpinder:
I am having to jump about a bit because I am not familiar with the boards you are talking about. I have looked at the KBIC boards and I assume that the spindle will turn - in other words, the board I have looked at has a pot you can turn and this controls the speed of the spindle. You say that the Mill is working OK, so I assume the board is working correctly and, like me you would like to go one step further and control the speed.

I notice that the board has an external input on pins P2(+) and F- (which I assume is 0v). This takes an isolated 0 to 9v signal to control the speed. The board I looked at does not appear to control the direction of the motor.

I notice also that the board is equiped with a pair of  "inhibit circuit" terminals (11 and 12). Are these jumpered. Do they only come into play when controlled externally.

I have the same problem with my Omron inverter. This has M3 and M4 inputs, and can have a pot to control the speed (although I use the digital panel on the front)
How are you proposing to control the speed. In other words, how are you going to generate the analogue voltage to put to the external inputs???

Mach3 will put out, on any of the designated output pins, signals for M3 (motor forward) M4 (motor reverse) and of course M5 (motor off) and I have these wired to drive relays via a Darlington array (four in all because I also did the coolant outputs at the same time)
These relays close contacts on my Omron motor driver to give forward and reverse.

You talk of hearing a relay click on the BOB - but what does this relay do - is it driven by the M3 output (which is an on/off output) and what is the relay connected to on your KBIC control board (if anything).

Does you KBIC driver board need any programming to change from internal to external control circuits - the Omron does.

We must assume you have done 90% of the job correctly if you have been using it for some time. If you send me a wiring diagram for the connections you have made for the spindle control - together with the Mach3 settings, I will try and help.

jimpinder@tiscali.co.uk  or just post on here.



jacmarhal:
Go figure! I post a question on this forum after weeks of frustration with my Mach3/ Taig mill setup and AFTER I post a question the whole damn thing comes to life!!  This forum truly is a magical place! ;D

Well, I've been away from the computer and my CNC setup for a few days due to frustration. I finally went back to it, turned on the computer and started playing with Mach3. Went to MDI screen and inputted M3S500 and my spindle came to life! I did not do anything differently other than downloaded a newer version of Mach3 ver. 2.6. That must of done the trick.

jimpinder, thank you for responding. Regarding the KBIC board; this is the speed control for my spindle. It is an analog unit with a pot that controls the speed of the spindle (outputs 0 to 90vdc). It can be controlled from an outside source by replacing this pot with a 0-10vdc signal. This is where my BOB comes in. It has a built in converter that takes the 0 to 25kHz(?) signal from Mach3 and transforms it to 0 to 10vdc. This board does not control direction of rotation. One would have to do this externally through relays etc... The inhibit circuitry on the KBIC could be used for dynamic braking and/or motor reversal. But I'm not there yet. The relays ( there is actually 3; 2 mechanical and one electronic) function on the BOB, is to apply power to the KBIC board. I then input a speed through Mach and the spindle rotates. I guess I could control the spindle through Mach3's S command, but I get a better warm fuzzy feeling doing it this way. :)

Alrighty then. Now that I've got that out of the way, I have a few more questions about spindle control.

In the spindle calibration and testing screen, there is a section that says pulses/rev zero for index pulse. This is set to one on the screen and should be zero as I am using an index pulse and there is no way to change it. Is this a bug or does it make any difference? Also, the RPM display; is this strictly a display or does it provide a feedback for Mach3 to control/maintain the speed of the spindle under various loads? And one more question. What does the spindle calibration actually do? I could not find any documentation on this feature.

Thanks in advance.

jimpinder:
I have an optical detector on my spindle, which gives one pulse per rev of the spindle. If you input this into the computer on one of the input pins, and then link this to the "index" input (which you will find on ports and pins/input), then it automatically calculates the revs per minute, without any other configuration at all. It is displayed on the front screen of both Turn and Mill

I find it works very well - but the only thing is I have a bit of difficulty with is checking to see if it is correct. I can specify a speed on my Omron inverter, by that is is hz/sec. I do not know how my motor is wired, and I do not know the step down ratios of my pulleys so I have a bit of a way to go yet - but at the moment my speed detector seems to be reading about 1/2 of what I think it should be.

There is a brief reference to this on the Inputs/Outputs tutorial video. I wish Art - (althoug I know they must be busy) - would do a video on the speed control and detection systems on Mach3 - I could sure do with one.

LarryL:
hi All,

This thread is new to me, but I have a question that I think is right down someones alley.  I have built a cnc quilter, some of you may have seen my posts under cnc quilter.  Now I am attempting to motorize the upper take up roller.  It has to move the roller clockwise or ccw 1 full rev when the carriage (Y axis) moves forward/reverse to the indexing point, or up against the back of the Harp or throat of the sewing machine  as it moves it will take up the quilt on the take up roller.  That part is pretty simple.  Now the hard part is this.  Every time the y axis moves forward to it's index point, the Takeup roller should roll up 1 rev.  This should repeat until the y axis reaches a limit point/switch where the y axis reverses direction and the takup roller now reverses as well and plays out the quilt while moving toward the rear of the carriage where it will reach a second limit point/switch, and reverse direction.  The question is this!  Can I use the spindle to control this action, and control the speed of the spindle and distance of rotation?  This motions are not continous, but will occur only when needed to keep the takeup roller away from the back of the sewing machine or away from the needle mechanism.

Hoping for a great answer!

Larry

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