I have a system which has 4 large storage tanks holding a liquid. The level of each tank is sensed by a Senix ultrasonic sensor with a 4-20mA signal going into the analog card of a SLC 500 plc. The sensor has 4 wires, with 2 being the power supply and 2 being the signal out. The common is shared. Everything works great. NOW... we are going to add another production line and use these same 4 storage tanks as a supply to the new line. Completely separate system but I need to share the 4-20mA level signal with this new system. I know this can be done with a signal splitter but I am not sure what exactly to buy. Two way or three way isolation. Any recommendations? Thanks.