Help requested - installing end stop sensors onto my chinese 3018 Pro

[favouritesky]

Hi all,

I've recently bought myself a chinese 3018 cnc from ebay and having played around with it for a couple of weeks have gotten a hang of most of the basics. I've been insipred by the likes of Cosmo Channel and Minh's Man Cave on youtube to add a few small upgrades onto it.
I'm not a total CNC newbie - I did a Mechanical Engineering degree way back when, so the physical side is fairly logical to me but I'm much less confident and competent on the electrical and programming side.
I managed to find a guide to GRBL settings and 'un-reverse' the Z travel direction (as the machine arrived with it reversed $=4 for some reason).

I'm now trying to install my limit switches, which is giving me a few more grey hairs...
I bought a set of these switches (based on the recommendation of Cosmo Channel); https://www.banggood.com/10Pcs-Geekc...r_warehouse=UK

The physical install and basic wiring has been ok, I've repurposed some leftover IKEA brackets as I dpn't have a 3D printer to make anything perfectly tailored yet.
I've managed to wire each pair of switches in parallel, carried out a little test by moving the bed and spindle into each switch and they seem to stop the machine OK.

* Question 1: I've connected the switches with the green wire to the + and the black to the - on the controller board - does that seem right?
The switch document says that;
"Red line connecting VCC (ramps of +)
Connect the black wire GND (ramps of -)
Green line connection Signal (ramps of s)" - which I can't say that I understand.

When I do depress the switch, I think the wires are starting to heat up until it is released and it disconnects the machine from my laptop.It also dims the 'P' LED, which illuminates when I have either power or USB connected, so it seems to be drawing current (forgive me for such a basic statement, electricity isn't my strong point!).
I haven't yet tried to deliberately crash into the limits whilst working to see what happens yet.

A lot of the guides online that I've found seen specific to Arduino or Woodpecker based hardware and I'm fairly sure mine is different, it's made by Shenzhen Moski Technology Co.


Here's a couple of photos of the controller board, not sure what else would be helpful to provide.

* Question 2: What behaviour should I expect when the switches are triggered? Is there a setting within GRBL so that instead of acting like an emergency stop, the spindle will retract back to a previous position? My assumption is yes, as that would seem likely to me for how a homing setup would work. So far I've just been moving the spindle manually from my G-code sender (UGS) - maybe it behaves differently during a proper cut?

Thanks in advance for anyone that read this far, and even more if you're able to offer any assistance!