The NEX NEM20 (Previously SPM20) Power Meter is a Multi-channel meter with easy to use clip on CTs. This page will briefly cover how to install the NEM20 meter, and how to set its communication settings.

The installation steps must be performed by a qualified electrician.

NEX NEM20 or SPM20

Installation

The NEM20 meter has three major components to be wired into it:

Three phase voltage

Phase A, Phase B, Phase C and a neutral line should all be wired into the NEM20 meter. This should be wired in wherever you would like to monitor the voltage from.

Communication bus

The NEM20 supports Modbus RS-485 communications. The data positive, data negative, and shield should be daisy chained into and out of the communication terminals.

CT Chains

The NEM20 has three RJ12 terminals - out of these you can daisy chain a string of it's special split core CTs.

NEM20 CT

Communication

Once the Communication bus has been wired in, you can enable Communications to the device by properly configuring its Modbus settings. The two settings you will need to change are the Baud Rate, and the Modbus Address. Set these to be compatible with the settings the NEX has been configured with. Generally, the NEX controllers will be set for 9600 Baud Rate.

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