DURAG D-LX 720 User Manual

17 Appendix II: Modbus
D−LX 200, D−LX 720 153
17 Appendix II: Modbus
17.1 General information
Slave Address
Function Code
Data
CRC
1 byte
1 byte
0 up to 252 byte(s)
2 bytes
CRC Low, CRC Hi
Table 17.1: Modbus RTU Message Frame
0
from 1 to 247
from 248 to 255
Broadcast address
Slave individual addresses
Reserved
Table 17.2: Modbus-Slave Address Range
The D−LX 200, D−LX 720 flame monitor supports the following Modbus
Function Codes:
Function Code
Function Code description
03
Read holding register (16Bit)
04
Read input register (16Bit)
06
Write Single Register (16Bit)
16
Write Multiple Register (16Bit)
Table 17.3: Modbus Function Code
If an invalid Modbus enquiry is sent to the D−LX 200, D−LX 720 this sends an
appropriate Exception Message as the response; e.g. if the Function Code is
not supported or if the enquiry is for an invalid data address.
If a Function Code is not supported, the Modbus exception 01 "ILLEGAL
FUNCTION" is returned.
If an attempt is made to read from or write to a non-existent or blocked
memory area, the Modbus exception 02 "ILLEGAL DATA ADDRESS" is sent.
Modbus FunctionCode(0x03..0x04) Read 16Bit Registers
(for details see Modbus-Specification)
Request
Slave Address
1 Byte
0, 1..254
FunctionCode
1 Byte
0x03…0x04
Starting Address
2 Bytes
0x0000 to 0xFFFF
Quantity of Input
Registers
2 Bytes
0x0001 to 0x007D
CRC
2 Bytes
SA, FC
DATA
Table 17.4: Modbus FunctionCode(0x03..0x04) Read 16BitRegisters Request

DURAG D-LX 720 Specifications

General

Brand	DURAG
Model	D-LX 720
Category	Monitor
Language	English