Mesa 7i37 - how to set pin between enable/brake?

Ok so here's my setup: Lagun FTV-3 mill, Mesa 5i20, 2x 7i29 drives, 7i37TA opto IO board

I've recently begun integrating some SSR's into the mill in order to control various tasks. To that end I've now got the 7i37 wired to 6 SSR's that control my servo power supply, enable the switches and contactors for the spindle motor, spindle brake, coolant pump, lube pump and a light mounted on the head.

Now, at current time I don't have the spindle really controlled by linuxCNC and while I have plans for a VFD in the future, I'm still a few months away from buying one. So I have an SSR which is tied in PNCConf to "machine enable" which controls power to the contactors that run spindle motor forward and reverse. That way, even though I must manually start the spindle, if I hit the Estop my spindle motor power is interrupted.

The downside of using "machine enable" however is that when I get to the end of a program, my spindle brake turns on but since the machine hasn't E-stopped or been turned off, my spindle is still running! Obviously this is NOT what I want to be doing, so is there an easy way to make sure that when spindle brake is on, the pin running to the spindle enable contactor is off, and vise versa, but can only enable when "machine enable" is also on? Thanks!

Thanks for the heads up on the VFD. Although, the reason I'm not running with a VFD yet is simply because I don't have the money right now, which is why I think its a few months out (maybe tax return time?)

I have a _very_ limited understanding of HAL and was hoping there would be a simple PNCConf way to do this because I'm annoyed by having to go thru my backup files and swap stuff back over every damn time I use PNCConf! But if there's no simple way I'll figure out a way to link them together using HAL, I wasn't sure if I should be using HAL or the classicladder to accomplish this task.

andypugh wrote:

greenbuggy wrote:

is there an easy way to make sure that when spindle brake is on, the pin running to the spindle enable contactor is off, and vise versa, but can only enable when "machine enable" is also on? Thanks!

Yes, but I don't quite follow your description.
Can you write out a little table of what output you want for each of the combination of inputs, and then we can figure out the logic?

Ok here goes:
Machine Enable + spindle brake on = pin off
machine enable + spindle brake off = pin on
machine disable + spindle brake on = pin off
machine disable + spindle brake off = pin off

I think if you used spindle on and an edge controlled timer to turn off for a second would do what you want.

make it so when the spindle-on goes true to false, it uses the timer to break power.

You could use classicladder or HAL components to do this.

If I understand what your asking for

Chris M

This is a sample CL program I was thinking of.
the input is connected to spindle-on. It is edge sensitive - true only when going from true to false.
the output is connected to your spindle drive contactor. It is inverted so is normally closed, so you can turn the spindle on
The monostable is set for 1 second, which breaks the contact for 1 second.

Chris M

Got it!
For this example, on the 5i20 GPIO pin 40 is the spindle brake and GPIO pin 44 is the SSR that allows power to the forward/reverse contactor buttons and also the machine light (makes it simple to tell if I can start the spindle or not)