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Installation of the drive connection
Overview
This chapter contains:
• Information about the protocols that are used between SREA-01 and ABB drives,
• Information about the drive interfaces that can be used with SREA-01,
• Connecting instructions for different drive setups,
• Guides for selecting the correct connection method for each drive model and use
case.
WARNING! Before installation, switch off the drive power supply. Wait for five
minutes to ensure that the capacitor bank of the drive is discharged. Switch off all
dangerous voltages connected from external control circuits to the inputs and
outputs of the drive.
Note: Arrange the bus cables as far away from the motor cables as possible. Avoid
parallel runs. Use bushings at cable entries.
About Modbus networks
SREA-01 uses the Modbus protocol to connect to ABB drives. The Modbus protocol
was introduced by Modicon, Inc. for use in control environments featuring Modicon
programmable controllers. Due to its ease of use and implementation, this common
PLC language was quickly adopted as a de-facto standard for integration of a wide
variety of master controllers and slave devices. Modbus is a serial, asynchronous
protocol. Transactions are half-duplex, featuring a single master controlling one or
more slaves. While RS-232 can be used for point-to-point communication between a
single master and a single slave, a more common implementation features a multi-
drop RS-485 network with a single master controlling multiple slaves.
The Modbus specification defines three distinct transmission modes: human-
readable Modbus ASCII, binary-mode Modbus RTU and Ethernet-enabled Modbus/
TCP. In serial-mode communication, the RTU mode is used by ABB drives.
Depending on the setup, either RS-232 or RS-485 is used. With Ethernet fieldbus
option modules of the drive, the Modbus/TCP can be used.
With drives as slaves, SREA-01 can act as Modbus master in a point-to-point
RS-232 connection, multi-drop RS-485 connection or in Modbus/TCP connection. In
addition SREA-01 can act as a Modbus/TCP gateway that connects to the drives by
Modbus RTU and offers access to the drive data by Modbus/TCP.
Installation of the drive connection
29
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