Advertisement
The serial port configuration is: 9600, 8, 1, N, N. The sensor is addressed as "Any address" (0xFE).
Input Registers Description
Values are read from IR using "Read input registers" (function code 04).
Read Detector Temperature
Master Transmit:
<FE> <04> <00> <04> <00> <01> <64> <04>
Slave Reply:
<FE> <04> <02> <30> <D4> <51> <9A>
Data Explain:
<30> <D4> is valid data 0x30D4, decimal is 12500. After conversion (divided by 100 first, then subtract 100), it is 25
degrees Celsius. Note that the detector temperature is usually higher than the ambient temperature.
Read Meter Status
Master Transmit:
<FE> <04> <00> <05> <00> <01> <35> <C4>
Slave Reply:
<FE> <04> <02> <01> <60> <AC> <9C>
Data Explain:
<01> <60> is valid data 0x0160, the binary is 0b101100000, the 0th bit of the data bit is DI1, the first bit of the data bit
is DI2, and so on. The valid bits are as follows:
DI 6 - Out of Range
DI 7 - Memory error
Read Output Status
Master Transmit:
<FE> <04> <00> <06> <00> <01> <C5 > <C4>
Slave Reply:
<FE> <04> <02> <00> <03> <ED> <25>
Data Explain:
<00> <03> is valid data 0x0003, the binary is 0b11. The valid bits are as follows:
DI 1 - Alarm Output status (inverted due to Open Collector)
DI 2 - PWM Output status (1 means full output)
Read Space CO
2
Master Transmit:
<FE> <04> <00> <07> <00> <01> <94 > <04>
Slave Reply:
<FE> <04> <02> <01> <90> <AC> <D8>
Data Explain:
<01> <90> is valid data 0x0190, decimal is 400 ppm.
Read PWM Output
Master Transmit:
<FE> <04> <00> <08> <00> <01> <A4 > <07>
Slave Reply:
<FE> <04> <02> <3F> <FF> <FC> <94>
Data Explain:
<3F> <FF> is valid data 0x3FFF, it represents 100% output, i.e. 2000 ppm CO2.
Tel: 07788 548013
solentgasconsultants@gmail.com
Honeywell CRIR-M1 User Guide
MODBUS FUNCTION DESCRIPTION
Advertisement
