29
Description
ModBus slave device ID
Base address of holding registers for the raw values
Base address of holding registers for the range-scaled values
Base address of holding registers for the scaling factors
Base address of holding registers for the transmitter battery levels
Base address of holding registers containing the transmitter counter
Base address of holding registers containing the ages of each value.
When reading the values from the RC250, the only Function Code that can be
used is 'Read Holding Registers' (0x03). It is possible to read several registers at
a time using the Quantity of Registers field, but note that RC250 is limited to
50 registers at a time.
NB. The address values used in the RC250 protocol are the actual addresses
encoded in the Modbus message. Some host communication software
requires ModBus Holding Registers in the form 4xxxx or 3xxxx. With this
scheme, what is referred to as 'Holding Register 40001' is actually addressed
within the message protocol as register address 0000 (not 0001 or 40001). It
is very important to ascertain exactly what convention the host software uses.
