Gnd and Low? The laser connections on my Ruida controller are Gnd, L-On1 (laser on), and LPWM. The PWM output will be ramped up prior to firing, which is toggled by L-On1. You might need to change the tube type in the Machine Settings to be an RF tube without pre-inition instead of glass, as I think they just use the PWM output without the L-On signal, but I’m not certain. I’ve never used a diode laser with a Ruida before.