Specifications

Section 7. Measurement Instructions
SDMSIO4 (Dest, Reps, SDMAddress, Mode, Command, Param1, Param2,
ValuesPerRep, Multiplier, Offset)
The SDMSIO4 instruction is used to control and transmit/retrieve data from a
Campbell Scientific SDM-SIO4 Interface (4 Channel Serial Input/Output
device). See the SDM-SIO4 Serial Input Interface manual for operation
details.
For instructions used for serial input and output without the SDM-SIO4, see
Section 12.
Parameter
& Data Type
Enter
Dest
Variable or
Array
The Dest parameter is the variable in which to store the results of the
instruction when retrieving data from the SIO4. If data is being sent to the
SIO4, then Dest becomes the source array for the data to be sent. The Dest
array must be at least as large as the Reps parameter value multiplied by the
ValuesPerRep parameter value.
Reps
Constant or
Expression
The Reps parameter defines the number of sequential SIO4s that will be
called by the instruction. The datalogger will poll the SIO4 with the address
set by the Address parameter first, receive or send the number of values set
by the ValuesPerRep parameter next, and then poll the SIO4 with the next
sequential address. If the Reps parameter is 2, the ValuesPerRep is 3, and
the Command parameter is set to receive, then three values from the first
SIO4 would be sent to the first three elements of the Dest array, and three
values from the second SIO4 would be received and written to the forth
through sixth elements of the Dest array.
SDMAddress
Constant
The SDMAddress parameter defines the address of the SIO4 with which to
communicate. Valid SDM addresses are 0 through 14. Address 15 is
reserved for the SDMTrigger instruction. If the Reps parameter is greater
than 1, the datalogger will increment the SDM address for each subsequent
SIO4 that it communicates with.
The SDM address is entered as a base 10 number, unlike older, jumper-
settable SDM instruments that used base 4.
Mode
The mode parameter defines which port the instruction will affect.
Code
Description
1 Send/Receive Port 1
2 Send/Receive Port 2
3 Send/Receive Port 3
4 Send/Receive Port 4
5 Send to all Ports (global)
Command
The Command parameter is used to configure the SIO4. The commands are
listed briefly below. See the SDM-SIO4 manual for details.
Code Description
1 Poll of available data.
2 Get EPROM and memory signatures.
3 Flush all receive buffers.
4 Send data to datalogger.
5 Return number of watchdog errors, invalid command
executed, and lithium battery voltage.
6 Flush transmit buffer.
7 Activate command line.
8 Poll TX buffers for data.
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