Operation
X-320M™ User's Manual
3.4.4 Read Sensors – Modbus Function Code 03 (0x03)
The Read Holding Registers function is used for the sensors, calculated values, and high/low values.
Request
32-bit sensor values are read from 16-bit register pairs. Consequently, senors addresses and registers
must be even numbers.
All sensors and data values
Start Address: 0x0510 (Wind Speed Sensor) to 0x0540 (Yesterday's Low Humidity)
Input Quantity: 0x0002 to 0x0030
Response
32-bit floating-point values are returned, either as little-endian or big-endian numbers, depending on the
configuration in the
Advanced Network
tab.
With little-endian ordering, a temperature reading (0x0516) would return 0x800042A2. The least
significant word would be 8000 hex and the most significant word would be 42A2. This hexadecimal
value converts to a temperature reading of 81.25 degrees.
If a temperature or humidity sensor is not installed, a value of 0xFFFFFFFF (NaN) is returned. Other
inputs will show measured values of the open circuits.
Errors
Sensor Read Error Function Code (1 byte): 0x83
Exception Codes (1 byte):
0x01 – Function not supported.
0x02 – Incorrect combination of start address and input quantity
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