Reply to thread

Hi Klaus,

Thanks for the reply. I tried to write more about the use.

(Lets forget about the ground loop, I might not explain well but there will be no ground loop in this. Yesy that pic is not mounting holes but I put them(GISO grounds) to show that they are connected to one mounting hole(right bottom one). Other ground to other three mounting holes. And all screw holes will use plastic standoffs.) The two grounds(GISO and the MCU ground) are only connected at a single point, because I added a keepout zone for the relay section. Why? I will explain below.

Let me try to write about why I asked if I need to remove the relay or not eben though all is 12VDC.

My main concern was: during relay switching would that cause sudden peaks and maybe affect other ICs in schantic such as the MCU. So I thought removing ground plane might mitigate if there is such bouncing. And it is just precaution. Maybe there is no bouncing and I don't know how to measure it as well to see if such thing exists.

What´s connected to the relay (contact side): It is a SW controlled driver and gradually ramps to 4A from 300mA to 4A. So after the relay switches contacts at 12V 300mA the driver starts drawing more current as a ramp. And likewise the SW gradually decreases current to 300mA. So the contacts switches ON only at 12VDC 300mA state. After relay is latched the carry current gradually ramps up by SW.

We don´t know who/what controls the relay (coil side):  Coil is controlled by a push button. The relay is wired to be sued as latching action. So a push button energizes and latches the relay via 12VDC.