... %, 50/60HZ ApplicationWidely used in environmental protection, sewage treatment, thermal power, breeding, food processing, printing, metallurgy, pharmacy, fermentation, chemical industry, ... divided into high and low alarm control.9.Signal isolation output: 4~20 mA isolation protection output10.Relay: relay lag ... online PH controller/PH probe/water treatment PH analyzer with signal output 4-20mA