[skray775]

Hi Guys,

I have the Dmm Breakout-Board DMB4250-8B.

I want to set up a relay to control the coolant flow via air operated solenoid. I use mist coolant so I just need to start and stop the air flow.

The only output I have left is Dout 17. Dout16 is in use with the VFD.

I set up output #4 in Mach3 to pin 17 and use the m7 command to start the mist.

Question, if I have this set up right shouldn't Dout 17 have some voltage across the pins? I am reading 0 volts on all 3 pins?

Thank you for the help.

[scarlite]

The voltage source (+) should should be connected to D17. The solenoid positive (+) terminal (wire) should be connected to S17. Output 17 is a relay (switch) so once pin 17 is triggered, you will have continuity (not voltage) across D17 and S17.

D17 has a limit of 30 Volts 40 milliamps.

If using an external voltage source, keep it below 30 Volts and use a relay which draws less than 40milliamps to switch.

M7 will activate Mist
M8 will activate Flood
M9 will turn off coolant
The default "Program Run (Alt-1)" screen only has a flood coolant button ("Flood Ctrl-F). If you don't plan on modifying your buttons and only plan on using mist, my recommendation is to activate your mist with the M8 Output. This way you can toggle the button whenever you want instead of having to MDI "M9".

I haven't seen many air solenoid valves require less than 1W to trigger the switch.

I set up flood coolant using a standard automotive relay (12V - 450mW trigger). Instead of using an external voltage source, i used the on-board 12V from one of the limit switches. This allowed me to be below the power required to trigger the 12V relay (12V x 40 mA = 480mW).

On a side note, i have a 12V solenoid valve hooked up to pneumatic cylinder on the drawbar. Specs say the power draw is 3W (250mA at 12V). I only measured 95mA at 12.7V (1.2W).

If you keep this relay triggered while running a program, i'd recommend staying below the limit for continuous use. Since you posted 10 days ago, i'll assume you figured it out already. Just thought i'd pass along the info in case someone else was stuck.

[skray775]

Thank you for the reply. I decided to use the relay built into my VFD for the coolant. It was easier to configure and the coolant comes on whenever the motor starts.