Campbell SDM-IO16 User Manual page 25

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
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
Instruction 29 –used with older CR7s
Parameter Type Description
1 2 Reps (No. of modules sequentially addressed)
2 2 Device (2 = SDM-CD16/SDM-IO16)
3 2 Starting Address (base 4: 00..33)
4 2 Card (Excitation card No.)
5 4 Starting Input Location
Execution Time = 150 ms to 190 ms per Rep
Please note that these instructions use base 4 addressing. See the table with Figure
5 to see the matching setting of the address switch on the SDM-IO16 that equates
to any base 4 address.
The number of SDM-IO16s to be addressed is defined by the Reps (repetitions)
parameter. Each Rep sequentially addresses (00, 01, 02,...32, 33) SDM-IO16s,
starting with the address specified in parameter 2 (parameter 3 for Instruction 29).
For each repetition, the 16 ports of the addressed SDM-IO16 are set according to
16 sequential input locations starting at the input location specified in parameter 3
(parameter 5 for Instruction 29). Any non-zero value stored in an input location
activates (sets HI 5V) the associated SDM-IO16 port. A value of zero (0) de-
activates the port (sets LO 0V). For example, assuming two repetitions and a
starting input location of 33, outputs 1 to 16 of the first SDM-IO16 are set
according to input locations 33 to 48, and outputs 1 to 16 of the second SDM-
IO16 are set according to input locations 49 to 64.
For older CR7s with Instruction 29, the Device (parameter 2) specifies what type
of synchronously addressed peripheral is to be addressed. The Device code for an
SDM-CD16/IO16 is 2.
For Instruction 29 only (older CR7s), the Card parameter (parameter 4) specifies
which 725 Excitation Card is being used for the control port signals. The Reps
parameter does not advance beyond the specified Card, requiring another
Instruction 29 for each 725 Excitation Card used.
and 21X Dataloggers
User Guide
15