Campbell Scientific SDM-IO16 16-Channel Input/Output Expansion Module - Manual (Page 20)

SDM-IO16 16 Channel Input/Output Expansion Module
reduction of the SDM-bus speed if the cables are long (see details of P115 in
the datalogger manual).
Parameter 08 specifies the number of the input location where data is either
read from or written to, depending on the command being used. This may be
the first location in a series of locations.
Parameter 09 is a multiplier that is applied to data read to and from input
locations. Normally you would set this to 1.000, unless applying a calibration
factor to data being read from the SDM-IO16.
Parameter 10 is an offset that is applied to data read to and from input
locations. Normally you would set this to 0.000, unless applying a calibration
factor to data being read from the SDM-IO16.
See programming examples in Section 7.
6.3.2 Instructions 104 and 29 (CR10, CR7, 21X)
Instruction 104 is normally used by the CR10/10X, CR23X, CR7 and 21X to
control the SDM-CD16(AC/D) digital output interfaces. Older CR7s used a
similar instruction (P29). These instructions can be used to control the output
status only of the SDM-IO16, as it emulates a SDM-CD16 if it receives
commands from the datalogger sent by this instruction and if the SDM address
of the module also matches that sent by the datalogger.
This can be useful if you need to use the SDM-IO16 in place of an SDM-CD16
or any of its later variants, or if you need to use one for output expansion only,
using a datalogger that has an old operating system that does not support
instruction P188 mentioned above.
If your datalogger does support P188 though, it is best to use that instruction as
commands sent to the SDM-IO16 are checked for corruption and resent if a
corruption is detected. This technique ensures more reliable operation,
especially in electronically noisy environments.
The Instruction descriptions are shown below.
Instruction 104 – SDM-CD16 used with CR10/10X, CR23X, CR7
and 21X Dataloggers
Parameter Type Description
1 2 Reps (No. of modules sequentially addressed)
2 2 Starting Address (base 4: 00..33)
3 4 Starting Input Location
Execution Time = 2 ms per Rep for the CR10/10X and CR23X
3.5 ms per Rep for the 21X and CR7
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