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Modbus Server Interface Points Definition
11.7. Modbus Server Interface Points Definition
The Modbus registers are fully configurable through the configuration tool; any point in the gateway can be
freely configured with the desired Modbus register address.
Every point defined in the gateway has the following Modbus features associated with it:
Feature
Description
#Bits
• 1 bit
• 16 bits
• 32 bits
Data Coding
• 16/32 unsigned
Format
• 16/32 bits signed (one's complement – C1)
• 16/32 bits signed (two's complement – C2)
• 16/32 bits Float
• 16/32 bits Bitfields
• Error comm.
Byte Order
• Big Endian
• Little Endian
• Word Inverted Big Endian
• Word Inverted Little Endian
Register Address
The Modbus register address inside the server device for the point.
Bit inside the
Bit inside the Modbus register (optional). The Intesis gateway allows bit decoding from generic
register
16 bits input/holding Modbus registers.
Some devices use the bit coding into 16 bits input/holding Modbus registers to encode digital
values. These registers are generally accessible using Modbus function codes 03 and 04 (read
holding/input registers).
Read/Write
0: Read
1: Write
2: Trigger
11.8. Modbus Client Interface
11.9. Description
The Intesis gateway acts as a client device in the Modbus TCP network, Modbus RTU client, or both.
IMPORTANT
Other Modbus devices connected to the network communicating with the gateway must always be
server devices.
The gateway supports communication with up to five Modbus TCP server devices.
For every defined point belonging to a particular Modbus TCP server device, a server address from 0 to 255
can also be freely configured. This feature offers great flexibility for installations. For example, when integrating
several Modbus RTU server devices connected in a serial line, with an RTU/TCP converter on top of this
serial line, it enables access to the RTU server points through TCP/IP. In this case, the RTU/TCP converter
communicating in TCP identifies the destination of the point (server address in the RTU network) by the contents
of the server address field.
Modbus TCP server devices are characterized by their IP address and predefined registers address map. This
address map specifies the address, type, and characteristics of the Modbus server device's internal points
(commonly called registers). These registers are accessible using the Modbus TCP protocol.
Communication parameters of the Intesis gateway (IP address, netmask, default router address, and TCP port)
are fully configurable to adapt to any IP network and server device.
USER MANUAL Version 1.0
IN701-KNX Series
Page 17 of 44
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