Hi Everyone,
My CNC Shield version is 3.00.
After grbl 0.9 update the Z limit signal pin (D11) has swapped with spin_enable (D12) , I confused which pin to use for control switch on & off for trimmer.
Is correct SpnDir pin to plug for Solid State Relay to control switch on/off for trimmer router or use Z limit switch pin?
I used this tutorial with mi cnc shield with grbl 1.1
Solid State Relay dont have 3 input like this blue relay on YouTube, it only have + and -
On that shield, I’m successfully using the pin marked as Z end stop on the board silkscreen as the Spindle Enable signal. Z- and Z+ are electrically identical so it doesn’t matter which you use. The “white” pins are signal, all the “black” pins are common ground. I’m using a relay rather than an SCR, but (assuming it can be driven by 5 volts) I’d expect to wire the signal to the + and ground to the - on the SCR.
By the way, you can also find 5v and ground in the bank of pins just above the Z limit pins.
Don’t forget that the output pins of the Arduino are rated for 40mA maximum. while a solid state relay is unlikely to exceed that operating current some (if not all) 5v mechanical relays will. As an example, the single relay shield for a wemos D1 I have takes 55mA and a different vanilla single 5v relay board takes 65mA OK…so it is not a lot out of spec, but it is out! The CNCshield does not have any buffering. I know thousands of people drive these relays directly off the Arduino and when (and if) they fail they just moan about the unreliability of the cheap Chinese Arduinos…