71M6513中性电流测量(Neutral Current Measurement)

The ability to measure Neutral Currents is a key feature to enable the user to enhance tamper detection  techniques. The current demo board firmware has the capability to measure Neutral Currents using the  Compute Engine (CE) Firmware.  All that is required is a minor modification to the existing demo board  and firmware, which will be discussed below.
 
To measure Neutral Currents, a 4th current input channel needs to be created to be used along with the  existing three voltage and three current inputs (VA, VB, VC, IA, IB, IC). The Neutral Current measurement  can be implemented using the existing 71M6513 demo board with minor hardware and firmware  modifications as given below:
 
Hardware Modifications: 
a.  The Neutral Current input can be connected to the 71M6513 Auxiliary input V3 (pin 86)
b.  Analog Auxiliary input V3 is measured with respect to VBIAS (pin 81)
c.  The input circuit for Neutral Current measurement is to be added as shown in the figure below: