Campbell Scientific SDM-SIO4 4-Channel Serial I/O Interface - Manual (Page 34)

Section 5. Programming the Datalogger
5-2
5.1.4 Parameters 4, 5 and 6 — SDM-SIO4 Command
This command (with up to two options) defines exactly what the instruction
will do. Where no options are needed, enter values of 0000 for parameters 5
and 6.
5.1.5 Parameter 7 — Values per Rep
This determines how many values to send or receive, starting from the specified
input location (parameter 8). Data can be either 4-byte floating point values or
single bytes, determined by the SDM-SIO4 command number.
Some commands require no input or output of values; for these commands this
parameter would be set to zero.
5.1.6 Parameter 8 — Starting Input Location
This is the first input location that values will be sent from or written to
consecutively until all values per rep (parameter 7) are done.
5.1.7 Parameters 9 and 10 — Multiplier and Offset
The multiplier and offset are applied to all incoming and outgoing data.
The multiplier should normally be set to 1.000; if left at 0.000
then zero value data will be stored.
5.2 Commands and Options (Parameters 4, 5 and 6)
For many of the command options listed below, it is necessary to leave a small
delay before calling another instance of the instruction which communicates
with the SDM-SIO4. This is required to allow the SDM-SIO4 to process the
instructions it has been given. Failure to allow these delays will probably cause
the SDM-SIO4 to return invalid data. The delays are called ‘Minimum delay’ in
the command descriptions.
Many of the delays vary with the parameters of the instruction, in which case a
formula is quoted to enable you to calculate the delay. All delays are in
milliseconds. The notation used in the formula is:
• floats is number of locations to convert.
• characters is the number of characters to each float value including decimal
point and sign.
• ports is the number of ports the value or values are being transmitted from.
This is 1 if parameter 3 in P113 is 1..4 or 4 if parameter 3 is 5.
NOTE