252
ICC
11.12
Modbus
11.12.1
Modbus/TCP
11.12.1.1
Modbus/TCP Client
11.12.1.1.1 Overview
The gateway supports Schneider Electric’s Modbus/TCP client protocol, release
1.0. The gateway is conformance class 0 and partial class 1 and class 2
compliant. Other notes of interest are:
•
Supported Modbus client functions are indicated in Table 9.
Table 9: Supported Modbus/TCP Client Functions
Function
Code
Function
Modbus/TCP Class
01
Read coils
1
02
Read input status
1
03
Read multiple registers
0
04
Read input registers
1
05
Write coil
1
06
Write single register
1
15
Force multiple coils
2
16
Write multiple registers
0
•
Supports up to 4 simultaneous connections (defined by the connection
objects) and up to 64 service objects.
•
32-bit register accesses are supported in a variety of options and formats.
11.12.1.1.2 Modbus/TCP Client Service Objects
The Modbus/TCP client protocol uses service objects to describe what services
the gateway should perform. For each service object, the gateway will continually
read the device data defined within the service object from the designated server,
storing the value(s) in the database (if the read function is enabled). When data
in the database changes where the service object is mapped, a write request is
generated to the designated server notifying it of the changed device data
value(s) (if the write function is enabled). For more information on configuring
Modbus/TCP service objects, refer to section 8.7.11.2.
11.12.1.1.3 Register and Discrete Mapping
Refer to section 11.12.2.1.3.
