... Electromagnetic Flow Meter Accuracy: 0.5% to 1% Communications: RS-232, RS-485,Hart, MODBUS BF-LDH Series Electromagnetic Flow Meter1 ... accurately measure the flow rate of liquids which are electrical conducting, caustic, and mixed with liquids and solids. ... Output: Upper Alarm-ALMH, Lower Alarm-ALML with photoelectric isolation;- Communications: RS-232, RS-485,Hart, MODBUS. Electromagnetic Flow Meter