Halytech
hydroSpider2 User’s Manual v1.23
Page 79
SDI-12 Type Options:
Device Address
: The address of the sensor, this may be numbers 0-9, letters a-z, and letters A-Z. As
the device address is unique, each SDI-12 sensor connected to a single hydrospider2 requires a
different device address.
Command
: hydroSpider2 is fully compliant with SDI-12 v1.3 and will support the following
commands: M, C, CC, R and RC. Which measurement command you choose to use depends on the
specifications for the sensor, consult your sensor manufacturer / manual to determine which is best
for you.
Parameter
: When the hydroSpider2 retrieves the sensor values via SDI-12, the sensor may provide
multiple values. The
Parameter
setting allows the user to choose which value the channel should log,
these are numbered from 1.
For instance (assume M/C command has already been performed):
0D0!0+4.45+47.3847-38.3489<CR><LF>
Response Parameter 1 = +4.45
Response Parameter 2 = +47.3847
Response Parameter 3 = -38.3489
To determine which parameter you require, consult your sensor manual.
Modbus-485 Type Options:
Device Address
: this may be any number between 1 and 255 inclusive. Since multiple Modbus
devices can be connected to the Intelligent Interface at any one time, each Modbus device must be
configured to have a unique address.
Function
: the function code determines what sort of read to perform. This information should be
listed in the sensor manual for each available register/coil.
Note: some manuals may list the function code in a format such as 40001. This is a convention left
over from when Modbus was in its infancy. Values between 1 and 9999 indicate a function code of 1,
values between 10001 and 19999 indicate a function code of 2, values between 30001 and 39999
indicate a function code of 4, and values between 40001 and 49999 indicate a function code of 3.
Data Type
: the data type option specifies how the retrieved data value is going to be interpreted by
the hydroSpider. The sensor manual should specify how the data from the sensor is encoded, and
this option should be set to match that description. Some type options have two alternatives where
one is LSW and MSW. LSW stands for Least Significant Word first and MSW stands for Most
Significant Word first, however the sensor manual may refer to these under different names (eg:
Little-Endian and Big-Endian, LSB and MSB). If it is not listed, it may be wise to use the Modbus
diagnostic output to determine which data type should be used.
Data Address
: this will be listed in the sensor manual for each piece of data 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 option field
Note: Modbus data addressing in the hydrospider2 begins at 0 as per the Modbus protocol
specification, however some manuals may start 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
