Campbell Scientific SDM-SIO4 4-Channel Serial I/O Interface - Manual (Page 36)

Section 5. Programming the Datalogger
5-4
Port 4 data available
| Port 3 data available
| | Port 2 data available
| | | Port 1 data available
| | | |
x x x x
If any of these four digits is greater than zero then data is available.
Values per repetition = 1
5.2.3 Command 2: Signatures
This command gets the SDM-SIO4 EPROM signature and the string memory
area signature; the two values are written into consecutive input locations. If the
signatures are zero then there could be corrupt data.
Values per repetition = 2
5.2.4 Command 3: Flush all Receive Buffers
Stored data in the SDM-SIO4 relevant to the port is also erased with this
command.
Values per repetition = 0
5.2.5 Command 4: Send Data to Datalogger
This command requests the SDM-SIO4 to send the specified (values/reps)
number of floating point values it has already received from the RS232 device
(relevant to the port specified) into input locations. -99999 is stored if no value
is available.
For example, this command could be used to get data converted using input
filter strings of type d, D, f, F, pn, bn, u[ ], vn[ ], wn[ ] and B[n,n..] – see
Section 3.
5.2.6 Command 5: Status
This command returns the SDM-SIO4 general status, lithium battery level,
errors and data available flags. The data is supplied as two floating point
values. First value:
Number of watch dog resets
| | Number of invalid commands executed
| | | Lithium battery level
| | | |
x x x x
Number of watch dog resets: This is a count from 0 to 99. This indicates that
there has been some hardware or software failure, or can be caused by the
datalogger transmitting the correct address but not transmitting any commands.