Model IR400 MODBUS
1
1.0 MODBUS RTU
1.1 Serial Communications Protocol for IR400
The default Modbus setup from the factory is 9600 baud, 8-n-1 format. The default
Modbus ID is 1. These defaults can be restored at any time by connecting the CAL_IO
wire (brown) to power supply common and then turn on the power to the IR400. After 10
seconds the CAL_IO wire should be disconnected from the power-supply.
1.1.1.1 Baud
Rate
The Baud Rate is a selectable setting via the Modbus Communications Interface. The
selectable baud rates are 19200, 9600, 4800, or 2400 bits per second.
1.1.2 Data Format
The Data Format is a selectable setting via the Modbus Communications Interface. The
selectable data formats are as follows:
Data Bits
Parity
Stop Bit
Format
8 None
1 8-N-1
8
Even
1
8-E-1
8 Odd
1 8-O-1
8
None
2
8-N-2
Table 1: Data Format
1.1.3 Modbus Read Status Protocol (Query/Response)
1.1.3.1 Modbus Read Query Message
Byte Modbus
Range
Referenced to IR400
1st
Slave Address
1-247* (Dec) IR400 ID (Address)
2nd
Function Code
03
Read Holding Registers
3rd
Starting Address Hi**
00
Not Used by IR400
4th
Starting Address Lo**
00-FF (Hex) IR400 Commands
5th
No. of Registers Hi
00
Not Used by IR400
6th
No. of Registers Lo
01
No. of 16 Bit Registers
7th
CRC Hi
00-FF (Hex) CRC Hi Byte
8th
CRC Lo
00-FF (Hex) CRC Lo Byte
Table 2: Modbus Read Query Message
•
*
NOTE:
Address 0 is reserved for broadcast mode and will not be
supported at this time.
•
**NOTE:
Start Address can be a maximum of 9999 Address Locations
(0000-270E)
Summary of Contents for IR400
Page 2: ......
Page 15: ...Model IR400 11 Figure 5b IR400 Mounting Dimensions with a European Box ...
Page 20: ...Model IR400 16 Figure 7 Wiring Diagram from IR400 to Control Equipment ...
Page 41: ...Model IR400 37 9 6 Engineering Documentation ...
Page 45: ...Model IR400 HART Field Device Specification for Point IR Gas Detector ...
Page 78: ...Model IR400 Infrared Point Detector for Hydrocarbon Gas Applications Modbus programming guide ...