Eastron SDM120C, User Manual, Page: 3 / 10

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1 Introduction
This document provides operating, maintenance and installation instructions.The unit measures
and displays the characteristics of single phase two wires(1p2w)supply, including voltage(V),
current(A),power(W),frequency(Hz),power factor(PF),active energy(kWh).The non-displayed
parameters of imported and exported energy can be read via RS485 communication with
corresponding register.
The meter is self-power supplied when it’s connected with single phase two wires system,does
not need to input a auxiliary power supply.It’s directed connected,does not need to connect with
external current transformer(CT).Built-in interfaces provides pulse and RS485 Modbus RTU
outputs.
1.1 Unit Characteristics
The Unit can measure and display:
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Voltage

Current
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Power

Frequency

Power factor

Active energy
Two pulse output indicates real-time energy measurement. An RS485 output allows remote
monitoring from another display or a computer.
1.2 RS485 Serial – Modbus RTU
This uses an RS485 serial port with Modbus RTU protocol to provide a means of remotely
monitoring and controlling the Unit
1.3 Pulse output
This provides two pulse outputs,Pulse 1 is settable and can be setted into four different energy
output modes:
Mode 1 0.001kWh/imp(default)
Mode 2 0.01kWh/imp
Mode 3 0.1kWh/imp
Mode 4 1kWh/imp
Also,pulse 1 can be setted into three types pulse out modes.
Mode 1:Measures imported energy.Total energy=imported energy(default)
Mode 2:Measures imported energy and exported energy.
Total energy=imported exported energy
Mode 3:Measures imported energy and exported energy.
Total energy=imported energy-exported energy
Pulse 2 is fixed as 1000imp/kwh and cannot be setted.