How to Control Digital Outputs

Hi guys,

I'm still relatively new to LinuxCNC.

I'm currently using a leadshine mx3660 driver to control three stepper motors for a university project.

Ideally I want the ability to automatically take a photo of the progress of the experiment after each iteration.

The electronics guy at uni has wired up a FET switching system that closes a switch when a voltage is applied to the input. He tested it with an arbitrary power supply, and it was able to take photos with a camera with no issue.

However, I have currently been unable to operate this device with the digital outputs on the leadshine mx3660. I have selected digital out 1 for pin 17 in the stepconf wizard, as seen in the photo, which is connected to output 1 according to the driver manual.



In the .hal file, it even has the following lines:

net dout-01 <= motion.digital-out-01
net dout-01 => parport.0.pin-17-out

I was using this G-code to operate it:

G4 P1
M64 P1
G4 P0.3
M63 P1

However this has not worked.

The switch has an LED light as well which should light up when a voltage is applied to it, so I have used the following G-code to test it as well to no avail

G4 P1
M64 P1
G4 P10
M65 P1

Is there something obvious that I'm missing to be running the digital output? Because I'm not sure of what else to do to make sure the M64/65 codes work.

It is worth noting that when I hit run for the first time, I did hear the camera shutter when the motors started (not when it was programmed to), but it did not take a photo as it had in the past. So there is the potential that the box is broken too, but I wanted to check I had all the programing correct to begin with. I will be checking with the electronics guy tomorrow whether there is an issue with the box.

Any help will be really appreciated! If there's anything I've left out, please shoot

In the watch window the LED turns yellow when I run the M64 P1 command, which from what I gather represents the value as true? I did also add the digital out 0-3 pins in the watch space and ran the same commands and they also turned yellow as well, which I'm assuming isn't anything special?

I'd check that the physical output pin turns on & off on the mx3660 without the camera do-dad connected.

You have connected the pin from the mx3660 and GND to the camera do-dad ?

I'm currently checking the output pins on the mx3660 with a multimeter and the output pins are all reading 0V. (I reset up the configuration so digital out 0-3 corresponded to output 1-4, and used the m64 p0-3 commands individually in the MDI command window).

Should I check the actual pins on the db25 cable?

So we've checked the pins on the db25 cable and they are showing 3.3v on the respective pins and we have been able to turn that on and off within LinuxCNC, so that suggests that it's actually an issue with the leadshine mx3660 driver. So the Electronics guy is going to have a bit of a play with the driver to see how he goes.

Thanks heaps for the help guys!

EDIT: We have managed to figure out the problem and it is all working. Thanks heaps again!

I actually feel like a bit of an idiot... but the digital output didn't actually supply any power, it's just an electronic relay. Which in hindsight makes a lot of sense.

The manual didn't make it clear that it was just an electronic relay, but I'm assuming that might be commonplace with stepper motor drivers and I was just simply unaware of that through lack of experience.

The funny thing is that the reason we made the FET switching system was because we thought that the output actually output a digital signal, rather than being an electronic relay, so we could have realistically just used the driver outputs to control the circuit to take a photo rather than making up a box for it. But that's all part of the fun haha.