Page B-2
Airnet II Particle Sensor Operations Manual
Appendix B
Modbus Protocol
Input Registers
The input registers are in two sections: Configuration & Data
The configuration section contains:
•
Map Version
•
Firmware Version
•
Product Name
•
Flow and Volume Scale Factors
•
Flow Rate
•
Number of channels (Particle & Analog)
•
Particle channel sizes
The scale factors are values representing the power of 10 associated with the fixed
scaling of that parameter in the map. The channel sizes are in two registers
representing integer nanometers.
The data section starts with configuration information – Calibration date and serial
number. This allows for a single contiguous read when this particular information is
desired along with the regular sample data. If not desired, then skip this section and
begin reading at register 30212.
The Device Status register contains all the Coil bits for convenience. The host can use
this to check for data availability, for example.
The Device State register is a single register in which the
LSByte
is a state value and the
MSByte
is an associated sub-state value.
The time stamp set of registers is a "time_t" value.
The Data Packet Status is two registers for growth. 3 bits are used.
Flow Rate and Volume are in CF. These can be read either as integer values with fixed
scales or as Floats. The float mode is recommended to get best accuracy.
The location register is not utilized. It is intended for manifold systems (if applicable).
The number of channels and analogs varies across instruments by the purchased
options.
Table B-1
Input register – configuration
Input Registers
Description (Configuration)
Comment
Notes
30001
ushort
Modbus Map Version
Version 1.00 (Static 100)
30002
ushort
Sensor Firmware Version
Firmware version (*100)
30003
string
Product Name: Char 00, 01
Serial Number
30004
string
Product Name: Char 02, 03
Serial Number
30005
string
Product Name: Char 04, 05
Serial Number
