IntesisBox
®
BACnet/IP Server - Modbus TCP Master
User’s Manual r1 eng
© Intesis Software S.L. - All rights reserved
This information is subject to change without notice
IntesisBox
®
is a registered trademark of Intesis Software SL
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2. Interfaces
This section gives the reader an idea on how a Modbus TCP system/installation is integrated
with IntesisBox BACnet. It is not meant to provide an in-depth explanation on how BACnet
or Modbus TCP technology work as understanding the protocol principles is assumed
throughout this document.
The IntesisBox behaves as a regular BACnet device inside the BACnet system integrating all
the KNX devices. Note that each datapoint defined on IntesisBox will have two associated
data types:
One data-type, related to the BACnet/IP protocol of the IntesisBox
And another data-type, related to Modbus TCP side of IntesisBox
Conversions of data values from Modbus TCP to BACnet/IP data-types (and vice versa) are
internally performed at application level of IntesisBox, and keeping the highest possible
level of precision, with the restrictions of the data-type itself. Further detail on behavior and
data-types of the BACnet/IP and Modbus TCP interfaces of IntesisBox is given in the
following sections.
All configuration of IntesisBox BACnet is done using software tool
LinkBoxBacnet
. This tool,
covered in depth in section 5, is used to define the Modbus TCP and BACnet related
parameters on each of the datapoints defined in IntesisBox.
2.1 BACnet
The IntesisBox integrates all the Modbus TCP devices in a single BACnet device. The
communication with the other BACnet devices is done via the Ethernet port of the gateway
which implements the BACnet ASHRAE 135 – 2001 Annex J - BACnet protocol.
The supported BACnet Objects and Building Blocks can be found in the PICS document
available on the web:
http://www.intesis.com/pdf/IntesisBox_BACnet_IP_Server_Modbus_TCP_master_PICS.pdf
Configuration of all BACnet/IP parameters of IntesisBox and their links to Modbus TCP using
LinkBoxBacnet software tool is covered in section 5.1.
2.2 Modbus TCP
Modbus TCP communication is characterised basically by the embedding of the Modbus RTU
protocol into TCP/IP frames. This communication over TCP/IP allows faster communication
and a longer distance between master and slave devices in comparison with RTU
communication over serial line, and can use common TCP/IP infrastructure in buildings as
well as communication over WAN or internet. It allows also the co-existence of one or more
masters and of course one or more slave devices in a given network, all of them
interconnected through a TCP/IP based network.
IntesisBox acts as master in the Modbus TCP network, and the other Modbus devices
connected to the network communicating with IntesisBox must be always slave devices.
Up to 5 Modbus TCP slave devices can be defined in IntesisBox, to communicate with them.
