17. Modbus
17.1 Modbus in the controller
17.1.1 Overview
Modbus is generally accepted as a standard communication protocol between intelligent industrial devices. This means that the
Modbus protocol is used as a standard method to represent and communicate data in intelligent industrial devices.
The controller includes a built-in Modbus TCP/IP slave. The Modbus TCP/IP slave allows external devices to communicate with the
controller using the Modbus TCP/IP communication protocol. For example:
•
A PLC can request that specific data is read from the controller, such as the settings for the nominal AC configuration.
•
A PLC can send commands to the controller using the Modbus TCP/IP protocol.
This document will only describe the information required to communicate with the controller using the Modbus TCP/IP protocol. For
more information about Modbus in general and the Modbus TCP/IP protocol, refer to the documentation freely available at
Refer to the Modbus tables, available for download at
, to see how the controller data is mapped to the Modbus
addresses.
INFO
All values in this chapter are decimal values, unless specifically stated that a value is hexadecimal.
17.1.2 Warnings
DANGER!
The DEIF controllers do not include a firewall or other Internet security measures. It is the customer's own responsibility to
protect the network. The controller provides no access restrictions (for example group and user permissions) when
accessed through Modbus TCP. If the controllers are connected to a network connection outside of the controller network,
the controller can be accessed and configured through Modbus TCP by anyone connected to the network.
DANGER!
All controller settings can be accessed and modified through Modbus TCP. This includes disabling critical controller
protections by changing settings and alarms. Use the Modbus tables provided by DEIF to ensure that you do not disable
critical protections.
17.2 Modbus implementation in the controller
17.2.1 Modbus TCP protocol
The controller uses the Modbus TCP protocol to communicate with an external device over the Modbus network and through the
internet. The communication protocol uses static IPv4 addresses to send information. Dynamic IPv4 addresses (created by a
dynamic host configuration protocol server (DHCP server)) and IPv6 addresses are not supported by the controller for Modbus
communication purposes.
More information
See
Tools, Communication, Configure communication
in the
Operator's manual
for more information about how to
configure the controller communication information.
17.2.2 Modbus communication port
By default the controller uses port 502 (standard for Modbus TCP protocol) for TCP communication. Create a custom Modbus server
to use a different communication port.
DESIGNER'S HANDBOOK 4189340911K UK
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