#i have a cnc machine with a vfd controlled spindle. the breakout board is only 5v without onboard relay for turning on the spindle so i bought a 12v relay module and a mosfet module as well as a 12v power source.
12v feeds both the mosfet + and - as well as the relay + and -
i have the signal to the mosfet from the breakout board.
then the relay module is hooked up to the vfs terminals Xgnd and fwd.
when i trigger the 5v signal to the mosfet i can hear the 12v relay clicking and the status led turns on, however, with a multimeter on the com and NO terminals (same with the NC terminal) i get 0v being output.
the relay module is set to trigger high, if its set to trigger low, nothing happens at all when the mosfet signal is applied and removed.
reason im asking about this here is because im using an arduino to simulate the breakout board of the machine testing it all at home before i install it into the machine. im not sure why im not getting any voltage coming out of the relay when i can hear it clicking.
yeah, i have the 12v going into the inputs on the relay, so when the relay is activated, should the no and com receive the 12v and be able to be measured on the multimeter?
if im getting this wrong, i know its a little cheeky to ask, but could you modify the image i provided in order to show me what the wiring actually needs to be?
No, the NO and common contacts should just close when the relay is activated just like any switch. No voltage should be present on either of them. It is up to you to provide it
Use the multimeter to confirm that is happening although, if you can hear the relay clicking then it is almost certainly working OK
i’ve been instructed that to get the VFD to start and stop the spindle, the FWD and XCOM needs to be bridged via a relay, hence this whole setup. the idea is that the relay bridges the 2 terminals on the VFD however the FOR doesnt output any voltage as far as i can tell. that will need to wait till monday for me to put the multimeter on them and check. which is frustrating because monday is the deadline to get this section of the project functional.
however, for the sake of testing to ensure it is functioning, can i jumper 12v from the power supply to say, NO connection and use the multimeter to check if the connection is opening and closing?
Your mosfet module is for negative side switching. Your image shows you try to switch positive.
But with your relay module, you don't need that mosfet at all. It works with 5V signal.
not sure how i could have wired it wrong, it literally has one terminal for the signal, i tried it with a +5 line and got no reaction from the relay, i did the same with a 12v line and got it to click
wel, the mosfet module does connect to the common. but it uses the 5v as the actual trigger then closes the “gate” on the mosfets to pass the 12v through which the relay module then picks up that 12v and energises the coil as its designed to take a single + signal of 12v
Don't connect anything to the NO, NC or COM.
Just set your meter to ohms or beeper if it has it. If the contacts close then it should read almost zero ohms or beep
