Technical information

5. Modbus Network Installation

5.1 Overview

PV Powered commercial inverters can communicate via Modbus RS-485 and Modbus

TCP/IP. This chapter explains how to communicate with a PV Powered commercial

inverter on a Modbus network through either RS-485 or TCP/IP. This chapter is written

for PV installers, electricians, controls contractors and Modbus network programmers.

5.2 Modbus Communication Protocol

Modbus is a serial communications protocol and is the most commonly used means

of monitoring and communicating between devices in the PV industry. The Modbus

protocol allows for communication between a Modbus master device and multiple

Modbus slave devices connected to the same network. The physical layer of the Modbus

network is a twisted pair shielded conductor for RS-485 and CAT5 Ethernet for TCP/IP.

5.3 Networking Using the Modbus Option

The following steps are required to set up a Modbus TCP/IP network for your PV

Powered inverter:

• Field Installation Process

This step can be completed onsite by a PV installer or an electrician that does not

have working knowledge of a Modbus network:

• Consult the facility IT administrator for network device installation support

and coordination.

• Install the Modbus network communications cabling.

• Modbus Network Conguration Process

This step can be done onsite or remotely and should be completed by the

Modbus network programmer:

• Set the IP addresses and Port ID for TCP/IP.

• Congure the point maps for slave devices.

5.4 Modbus TCP/IP Installation Process

Disconnect the power to the inverter before starting the installation.

DANGER

AC and DC voltages will still be present at the inverter AC and DC

landing points unless utility connection circuit breaker and PV array

inputs are disconnected.

MODBUS

INSTALLATION