TELEDYNE API 480L, User Manual

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42 Teledyne API Model 480L O
3
Monitor User Manual 09419A DCN8342
6.3 MODBUS REGISTER MAPS
6.3.1 MODBUS COMMANDS SUPPORTED
Table 6-2 lists the MODBUS commands that are supported by the 480L. Note that
the “Write” commands will only work with registers that are configured as
Read/Write, see Section 6.3.4. The “Read” commands can be used with any
register.
Table 6-2. Supported MODBUS Commands
MODBUS
Function Code
Description
01 Read Coils
02 Read Discrete Inputs
03 Read Holding Registers
04 Read Input Registers
05 Write Single Coil
06 Write Single Register
15 Write Multiple Coils
16 Write Multiple Registers
Float Inverse data format:
IEEE-754 encoded 32 bit floating point values stored in 2 sequential registers as
shown below:
Value Stored in
Memory
Register 1 Register 2
0x12345678 0x5678 0x1234
6.3.2 NOTES ON MODBUS REGISTERS
Concentration values in the MODBUS registers are always expressed in units of
PPB (parts-per-billion,) regardless of the concentration units setting of the monitor.