Two-wire current loop circuit for measurement transducer - has two buffer amplifiers, differential amplifier, voltage limiter in fully integratable design

摘要

The two-wire current loop includes two buffer amplifiers (OP1, OP2, R9, R10, R11) with supply ports connected to node points and inputs connected to signal outputs of the measurement transducer (MA). Resistors are connected between the buffer amplifier outputs and inputs of a differential amplifier with supply ports connected to the two node points. Further resistors are connected between the second node and one input or the output of the differential amplifier. Fifth and sixth resistors are connected between a first line connector and the other amplifier input or second node. A voltage limiter (SB) is connected between the other line connection and the first node, with its reference port connected to the second node. ADVANTAGE - High absolute accuracy, fully integrated circuit.