... available 3.1-4 alarms,analog output HA series Digital Thermometer & Hygrometer Features: 1,Input:dual line displaying temperature and humidity ... settable,2 alarm output either temperature or humidity selectbal,with high,low and intervals alarm mode selectable.3,Isolated ... ,Communication:RS232/485 interface,MODBUS RTU protocol,directly connect with PLC,computer and other equipment..6,Width power supply ...