... ,NO: 4-20mA, 0-10mA signal ouptut:RS485, RS232 communicationAlarm type : High and low limitsCommunication : RS485 or RS232 ,MODBUS-RTU protocol ... and performance ammeter, voltmeter, current meter, voltage meter, power meter, pannel meter, ohmmeter, high-impendence ohmmeter DP4-RMS Intelligent Digital DC/AC Ammeter/Volmeter