Phoenix CNC Controller GRBL 1.1e GRBL Panel 1.0.9.15 I have the "Coolant" and its associated ground going through a JQC-3F(T73) relay. The relay triggers a small water pump which is what sprays the coolant onto the end mill. When the controller is only being powered by my PC, everything seems to work fine. I say "seems" only because I can not trigger the coolant port without main power. Problem: When the controller is only being powered by both my PC and it's 24V power supply, activating "M8/M9" (coolant on) causes the controller to quickly disconnect and reconnect. This is the equivalent to physically disconnecting the controller form my PC. Once that happens, GRBL Panel freezes, which is to be expected. During the disconnect/reconnect jump, GRBL Panel does not change it's connection status. The "digital" status remains connected. In order to regain control, I must digitally disconnect and reconnect. The following initialization is a bit weird. I have not been able to confirm exactly what happens after as it initializes a little differently each time. The coolant signal is 12V. One thing I thought about was resistant...or lack of. The picture below is directly from the creater of the board. Would adding a resistor help? If so, any recommended value? Thanks, Kevon
The relay coils are driven off of 12 or 24VDC. If you do not connect 12/24VDC, the problem doesn't happen? I think that is what you said. If true, then it is the relay on the controller board generating some sort of noise that is feeding back into the microprocessor circuit and resetting it. You could try isolating the relay from the board to see if it's the magnetic coil that's causing the problem. It appears that the board's 5V comes from USB so there should be isolation of the microprocessor's +5V rail from the 12/24VDC of the relays but there could be some sort of magnetic pickup from the relay if the 5V rail passes near it. One thing to check is to give the relay power but not connect the pump. Does the same problem happen or not? Also, make sure the USB cable doesn't go anywhere near your pump. I'd get a USB cable that also has at least a ferrite choke on it near the controller board. Even better, a shielded cable. [edit] to you question about a resistor. I don't understand where you would put it.
Hi Kevon, Just wrote you an email for the solution that got figured out by another customer of mine. It all boils down to the power input setting. The problem occurs if the setting is on 12 volt input and the smallest over voltage causes the interruption of the USB connection. So if your power supply is over 12 volt you need to set the input selector switches to position 2. I also finally made a new wiring diagram that I will attach here and have updated on my Tindie page too. If there is anything else I can help with, please let me know. Thanks.
Sorry for not responding sooner. I'll double check to make sure the jumper is in the correct position. Thank you.
What's the spec on the relay your using ? and can that transistor handle switching the coil ? I had a similar issue with a Arduino project it was powered via usb as soon as you used external power, The voltage would drop on the usb, I played with various value resistors until I got the pull up value right on the output - the internal resistors on chip can not be trusted
The spindle relay uses the same transistor and the same relay and has no problems. I don't see that the resistor value being the problem.
Do you get the same issues if you use ugs rather than grbl panel ? What psu are you using ? and what's it rated to ? what is the spec on the pump ? what voltage reg is on the board (found it - 78S12) and does it get hot ? do you run a heat sink on it ?
My other customer had the issue with all g-code senders he used until he figured out it was the power selector switch.
