How to give input connections to ADE7878 for 3-Phase 4 wire in to 3-PH 3 Wire?
The ADE7878 can be configured to accept multiple different configurations including 3 phase 4 wire and 3 phase 3 wire wye and delta. Our FAQ: AN-639 that is available on our website has detailed diagrams of each connection on pages 12 and 13. Although these diagram specifically show an older device, the ADE7754, the connections for the ADE78xx are the same. The one exception to this is the 3 wire delta case where when using the ADE7878 phase B must be used as a reference and not phase C as shown in figure 8.
When selecting the different configuration the CONSEL bits in the ACCMODE register must be configured to the correct setting. This is shown in the attached table and further details can be found on page 48 of the ADE7878 data sheet..