Halytech
hydroSpider2 User’s Manual v1.23
Page 86
Device Address
: A number between 1 and 255 inclusive indicating the Modbus device address of the
FL900 unit.
Data Address
: This will be listed in the sensor manual for each reading that is available to be read
from the sensor. It can be any number between 0 and 65535.
Note: some manuals may list the data addresses in hexadecimal format (eg: 0x03E8), in which case
the address will need to be converted to a decimal number (0x03E8 -> 1000) before being entered
into the Data Address field.
Note: Modbus data addressing begins at 0 as per the Modbus protocol specification, however some
manuals begin their addresses from 1. In this case, 1 must be subtracted from the listed address.
This is not always made obvious in the manual, so if the sensor is returning an exception, it is worth
trying again with 1 subtracted from the data address.
Note: some manuals may list the data addresses in a format such as 40001. This is a convention left
over from when Modbus was in its infancy. To get the data address, remove the most significant
digit (leaving 0001) and then subtracting 1 (resulting in 0000), which is the data address to enter into
the Data Address field.
Note
: the RS-232 interface on the FL900 unit must be set to 19200 bps with even parity and one stop
bit.
