The per-group meters report to the central meter over a single communication bus. This article describes how to wire it.

The bus

• The Measurement Device group meters communicate with the Power Analyser central meter over an RS485 / Modbus connection.
• All Measurement Device units and the Power Analyser are linked together as a single bus system.

Terminating resistors

• Place a terminating resistor of 100 or 120 Ohm at each end of the RS485 bus — match whichever value is already present in the installation.

Cabling

You can use a standard CAT5 cable to interconnect the devices:

• One wire pair for the A and B connections.
• One wire pair for the Ground / C connection.
• The Ground / C connection may be omitted at the Power Analyser.

Quick checklist

• All meters daisy-chained on the same A/B pair
• Terminating resistors (100/120 Ω) fitted at both bus ends
• Ground/C wired (optional at the Power Analyser)