ABB CSU-2LV, Installation And Maintenance Manual, Page: 40 / 84

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ABB
ARC GUARD SYSTEM™ – CSU-2LV/2MV INSTALLATION AND MAINTENANCE GUIDE
6.4 Installation
6.4.1 General
Modbus RTU is a 2-wire, RS485-based field bus
communication system for parameter value exchange.
The implementation of the Modbus interface is based on
standards [1] and [2].
6.4.2 Connector
The supplied Modbus connector has the following pin
configuration:
Table 4 Modbus connector
Terminal EIA/TIA-485 name
ITr/IDv Description
+(B) B/B’ D1 Transceiver terminal 1
Terminator 1 input*
-(A) A/A’ D0 Transceiver terminal 0
Terminator 2 input*
DGND C/C’ Common Signal common
* If the device is connected as first or last device in a
multi-drop system, a 120Ω terminator resistor should be
installed between terminator inputs (A) and (B).
6.4.3 Cables
Recommended cable: Belden 3105A (AWG22).
6.1 Introduction
This chapter covers the Modbus interface, which offers a
direct connection to Modbus-RTU for the CSU-2.
CSU-2 will behave as a slave. This means all communication
will be performed by a master device on the same Modbus
system. Mostly this will be a PLC. This manual explains
how to install the CSU-2 to your Modbus system.
6.2 References
[1] http://www.modbus.org/docs/Modbus_Application_
Protocol_V1_1b3.pdf (2012)
[2] http://www.modbus.org/docs/Modbus_over_serial_
line_V1_02.pdf (2006)
[3] https://www.modbusdriver.com/modpoll.html
6.3 Quick start-up
To start-up the Modbus connection, do the following
steps:
1. Make sure your Modbus master has been installed
to the system.
2. The CSU-2 will be delivered with the following
configuration:
• baud rate 19200
• parity even
• stop bits 1
• Modbus ID 248*
*Modbus ID 248 is not a valid id for a Modbus
system but is used to indicate that the
communication is disabled, needs to be
changed to get communication to work.
3. Physically connect the system to the
Modbus network.
4. Test communication between your master and
the CSU-2.
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