X2 Speed Control Pot. Voltages

[maxboostbusa]

I am working on getting my CNC4PC C6 card to work still and have gotten it to run wide open all the time until I hit the e-stop. I did some voltage checking and my readings are opposite of what everyone else is getting and it doesnt make alot of sense. Between P1 (gnd) and P2 (wiper) in the off position I get the 11.99vdc. As the control is turned to increase the RPM's (which it does) the voltage drops in proportion to the spindle speed. I didnt buy this mill new it was used very little if it even made a cut but they had already been in the control box and adjusted the small Pots. for the speed and torque so I dont know if they had unhooked any wires or not. Any help would be appreciated. Thanks in advance.
Rick

[hoss2006]

The C6 can be a pain in the kiester, can't it.
I'm waiting for my 3rd from arturo to go into the new console.
I think it will be safe this time from shorting out since I ordered a 12v power supply just for it.
Your voltage readings are opposite what I got when I first tested it
but I am running a replacement circuit board not the original.
Still, I had the meter connected to the outputs of the C6 board not the pot.
I know the pot does work backwards, when you click it on(clockwise) it cuts power and when you cycle it all the way off(counter clockwise) it turns power back on.
I can't find the page on that but believe it has to do with the circuitry on the original board that prevents the motor coming on unless the switch is cycled off first.
Don't remember if it was from arturo or uncle rabid.
Hoss

[maxboostbusa]

Yeah the C6 can be a pain. This is my 2nd board. The first one blew all the lands off the board under the RJ45 plug. I got the thing to work a couple days ago then when I tried messing with it again the next day it wouldnt work again. I hadent changed anything so its really odd. I know that it seems to be real touchy on the voltage. I had one 12v powersupply rated at 400ma, under load the voltage would drop to about 10.9. I had another 12v 200ma and its voltage would stay up at about 12.6. Thats the one it worked with. The power supply may have bit the bullet and its not putting out enough. I havent checked it yet, I got so fustrated with the board not working that I just walked off. I may email UncleRabid and see if its normal for the voltages to do like they are at the Pot.. Thanks Hoss.
Rick

[The Blight]

I see lots of people using the C6 board, but very few using the Digispeed controllers. I havn't had a chance to test it yet, but I hope to do so soon. I have 2 and I hope I can get them to work without blowing anything up. Sounds like the C6 boards are firecrackers.

[skmetal7]

I have the same problem as you and I determined it is the sieg spindle control. I can confirm that the voltage does decrease as spindle speed increases, see video. I hope not all dc motor speed controllers are like this . So either I won't have spindle speed control, or I'll have to look for a new controller.

"http://www.youtube.com/watch?v=eIlaX71-hck"]YouTube - Sieg x2 Speed Control

[hoss2006]

I went back thru some pics from my replacement circuit board project and
the C6 wiring for the ATC.
I apparently used P2 and P3 for the C6 board. maybe I was having the same problem and tried it with the wires switched.
This is the way that it worked in the video.
May be worth a try.
Hoss

P.S. I just got the new C6 and it's quite different from the one I originally used.

[brendanjerwin]

[QUOTE=skmetal7;443806]I have the same problem as you and I determined it is the sieg spindle control. I can confirm that the voltage does decrease as spindle speed increases, see video. I hope not all dc motor speed controllers are like this . So either I won't have spindle speed control, or I'll have to look for a new controller.

A potentiometer is a variable resistor used as a voltage divider. It's affect on voltage can be exactly what you saw. Most speed controllers control the speed of the motor with PWM (turning it on and off with varying duty cycles) and the potentiometer is used to control that pulse.

[skmetal7]

oh yeah thats right hoss, you are using a different speed control, then thats why yours works :P

[hoss2006]

Hey it's only $30 more.
Then you could sell the original board on Ebay

[The Blight]

Okey making a little guess here. The SIEG speed controller has 3 terminals for the pot. My guess is that this is a simple voltage divider. When you turn the pot, the voltage should decrease between the center tap on the pot and one terminal while increase between the other terminal and the center tap. So it's just about finding out which terminal to use. Try connecting a pot to the speed controller (SIEG), and measure the voltage between the center tap and both terminals.

PS. You want to use the terminal with the increasing voltage=increase in speed.

[skmetal7]

p1=gnd, p2=wiper, p3=~+12 volts (on the sieg controller)

[Crevice Reamer]

You are not measuring the control voltage, but the voltage dropped accross the resistor. (potentiometer) You need to measure from one terminal to ground to get the control voltage.

A potentiometer is a variable resistor. When you first turn it on, resistance is at its highest and you are measuring full analog voltage dropped across the resistor. As you turn it UP, resistance drops and measured voltage dropped across the resistance also drops. When it's turned all the way up, then there is no more resistance, so no measured voltage drop.

If you disconnect the wires and measure with an ohmeter, you'll see that the resistance goes from high at lowest setting to zero at highest setting--exactly as it's supposed to.

Now just imagine wiring the c6 so it takes the place of the pot. As long as the same wire gets zero to ten volts, (to ground) it will work.

CR.