PWM output on CNC BOB

[dazp1976]

I'm probably being stupid here, but - I assume the relay is for switching the spindle on and off. At the moment I'm just getting my steppers to work, and testing with Linuxcnc and the stepconf wizard. All the steppers are working, but every time I click on "test this axis" the relay comes on, even before I jog the axis. Why is this? When using the machine for real, I would only want the relay to come on when I want the spindle on, not when moving an axis. I don't have the 24V supply connected atm, if that is relevant

Change Enable to pin 14 and move any enable wiring there.
Then assign Enable1 as pin14 in Mach.
That should solve relay issue.
Looks like you have enable on pin17.

Then.
Pin17 is the spindle relay.
If you have seperate on/off & direction controls on the vfd:
Ports and pins I would suggest:
Spindle assign- step=pin 1, Dir=pin 16
Output #1 = pin17
Assign M3/M4 to output #1 (for on/off spindle)
Use pin16 for forward/reverse (I'd use a relay set up as NO=fwd / NC=rev)

Pin1 is the 0-10v/GND pins connected below where you plug in the 12-24v supply
Pin1 and all the other limit/estop inputs only work with this supply connected.
If you find that the ouput pin1 is 10v when stopped, change the active low/high level.

[jolyonjenkins]

Ah, thanks. That sorted it

[jolyonjenkins]

I have another problem. When the machine is on, but the computer is off, pin 17 (the relay) goes high and so the relay switches on. Do I need to pull it low?

[dazp1976]

I have another problem. When the machine is on, but the computer is off, pin 17 (the relay) goes high and so the relay switches on. Do I need to pull it low?

If you pull it low the relay will just work backwards.

You should always have Mach pc in control BEFORE you turn on the controllers themselves.
When finished. Turn off controllers first, then shut Mach pc down.

I used to get a relay flicker when powering on the pc, that was when I used usb for my 5v input.
I now use a seperate supply into the 5v & gnd terminals on the bottom row of the board for isolation.

[jolyonjenkins]

I find it a bit odd that it defaults to being high. I'm not sure if it's just floating up or whether this is intentional.
It it's floating, then a resistor ought to pull it down. I can't see that it will make the relay work backwards in any case.
I also use a separate PSU for the logic 5V, not from the computer.

[dazp1976]

I find it a bit odd that it defaults to being high. I'm not sure if it's just floating up or whether this is intentional.
It it's floating, then a resistor ought to pull it down. I can't see that it will make the relay work backwards in any case.
I also use a separate PSU for the logic 5V, not from the computer.

Those relays can be a bit of a chore. I never used it due to hearing it clicking away on startups.
There is a jumper next to the relay, so:
What I did is change the jumper setting so it uses pin17 screw terminal instead of the onboard relay for spindle on/off.
Got a seperate 5v relay with NO/ COM /NC contacts and hi/low trigger option and conect it to pin 17 output.

When PC is off mine sits in NC position. It will not trigger unless it has signal. Spindle switch is connected to NO. It only turns on spindle if Mach activates pin17 via 'spindle on/off'' button. It will NOT come on unless pc is on with mach running.
This will solve the problems.
I actually have a servo drive for mine. It's setup as: Pin17 is my on/off, Pin16 is my direction control.

Relay like this one below.
https://www.amazon.co.uk/Electromech...732588&sr=8-19
You can get them cheaper, this was just for quickness. Made more sense to me to buy multiple channel ones.
Being able to choose between high or low trigger I found quite useful.

Mine is an eight channel module. I have a few things with 5v negative to the trigger (jumper low). Also have a few things with 5v positive to the trigger (jumper high). Everything works perfectly with either polarity acting as triggers (as long as you set the jumper correctly). Great versatile little units :)