First time poster and Electron NOOB. I am trying to make a device to detect contacts closing in a float switch in a lift station and have it send a text message to multiple phones. I have an Electron mounted in a screw terminal breakout board from NCD. It works great on the bench (of course). My problems started when I put it in the field. First, some information about the lift station:
The control cabinet has a three phase, 100 amp, 208 feeder and a small transformer to pick off control voltage (120V), various controls, timers and alarms, and a GFCI receptacle.
The control cabinet has two NEMA size 2 magnetic starters. They alternate in use as needed. If an emergency happens (the highest float switch turns on), both starters pull in. There are several float switches, but only the highest one indicates an emergency. The other float switches pull in the motor starters as the fluid levels rise.
Basically I set a pin (D5) to INPUT_PULLUP and monitor it to see if it goes to ground. If so, it sends a txt.
I have a separate relay that closes a contact (grounds D5) when the highest float switch turns on. I have small power supply plugged into the GFCI and a battery for backup. All this works. My problem is that I get false alerts when either started pulls in.
Things I’ve tried so far:
- Move the relay and electron to another weather proof box outside the control cabinet - No help
- Put a ferrite core on the power supple cable - No help
- Plug the power supply into a separate power source - No help
- Run with just the battery - I received far less false alerts
Now I have the relay and electron in its own weather proof (metal) enclosure and disconnected the relay and power supply. It will STILL send txt messages out when either of the motor starters pulls in. This is without any power going to the relay that would ground D5! I can manually pull in the motor starters (relay still disconnected) and the electron will send a txt. It seems to me that the motor starters being pulled in is causing some type of EMI or something. I cannot seem to mitigate it.
Any thoughts would be appreciated.