I have a VM110 with 4 digital outputs (1-4) controlling (4) 12V relays switching 110V AC at extremely low amperage (about 0.06A). My problem is that when switching rapidly the VM110 will sometimes disconnect and reconnect or sometimes lock up all together (output 8 on solid until I un-plug and re-plug the USB cable).
I have the relays configured as designated on page 8 of the manual. I have tried this with and without the “clamp” pin connected but still have the same problems. I originally had the VM110 in the same electrical box with the relay board but have since moved it to a remote location to eliminate the possibility of magnetic interference from the AC voltage. This improved the situation some what but I still am having this trouble from time to time.
Do you think that the contacts on the relays could be arcing causing a power spike or something that shuts the board down as a safety precaution? The reason I think that is I have accidentally wired something to ground before and the board automatically shut down but reset itself after I corrected the problem and then unplugged and plugged the USB cable. What is the fastest rate the outputs on the VM110 are designed to switch?