I'm having trouble setting up Mach 3(V 1.9.070) for my mist coolant. I'm using a Hobby CNC board and CNC4PC AC relay card. If I connect from the 5VDC pad on the Hobby CNC board it will work. I get pin 16 to switch on & off & get 4.4 volts there. My CNC4PC DC card for my spindle works at that voltage. I've tried different pins, switching active high/low and can't get it to work. Anybody got any ideas?

Thanks
Mark

So are you seeing the pin change state ? If not what are the settings that you are using on the pin.
Thanks

Hi Brian,
My settings are Output 3, port 1, pin 17 & active high. I've also got the coolant set to output 3 on the spindle settings page. The LED  for pin 17 on the diagnostics page turns off and on & the wierd part is, I get 4.4 volts at pin 17, but it won't trigger the relay. The relay is good, it will trigger at 3VDC by hooking up 2 D cells.
I'm really confused, I've spent about 6 hours over the last week and no luck
Thank you for any ideas you might have

Mark

Anyone?
I'm wondering if I need a pullup resistor. The thing I don't get is why does it work on 3vdc from a battery but not 4.4 from the Hobby CNC board

 

Yup you need a pull up resistor.. you could look into getting a new SSR that would use a few less mA.   I think there are a few webpages that tell how to setup a pull up resistor.

Cool!
Thanks Brian
I'll give it a try

Mark