Campbell Scientific CR10X Measurement and Control System - Manual (Page 153)

SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-21
Command 0: the CR10X will issue the ‘M’ SDI-
12 measurement command and wait for the
sensor to complete its measurement before
requesting the data and proceeding to the next
instruction in the program table. If Instruction
105 is placed in Table 1, program execution will
be suspended during this delay. If it is placed in
Table 2, instructions in Table 1 may be
executed during this delay.
†Command 0--: this command enables
concurrent measurements with SDI-12 sensors
that support this feature. With concurrent
measurements, the CR10X can initiate
measurements with multiple SDI-12 sensors
without having to wait for each individual
sensor to complete its sequence before
proceeding to the next sensor. The CR10X will
issue the ‘C’ SDI-12 concurrent measurement
command and wait for the sensor response,
which includes the amount of time in seconds it
will take for the sensor to make the
measurement. The CR10X will not wait for the
data: rather, it will continue executing the table.
The next time the instruction is executed, the
CR10X will check the elapsed time. If the
elapsed time is equal to or greater than that
given by the sensor, the CR10X will get the data
from the SDI-12 sensor. In the following
execution of the instruction, the CR10X will
again issue the ‘C’ command.
The results of an M, C, M1-M9, or V command
sequence is numerical data, stored in input
location(s). The response to the I command is
text information, which is written directly to Final
Storage regardless of the Output Flag's state.
The
∗7 mode of the CR10X cannot be used to
view text data.
†In addition to the Standard SDI-12 commands,
the CR10X can issue ‘Extended’ SDI-12
commands. Instruction 68, Extended
Parameters 4 Digit, is used to supply the
characters and values to be transmitted.
Multiple Instructions 68 can be used
sequentially to extend the command string. The
Command parameter 2 in Instruction 105 must
be 0, not 0--. Parameter 4 in Instruction 105
should refer to the first Input Location, if any, to
be sent as part of the command string. The
parameters placed in P68 are the decimal
ASCII equivalent of literal characters to be sent,
or ‘128’ if the value in an input location is to be
sent. Enter a parameter of zero to end the
string. The address prefix and ‘!’ suffix are
automatically sent in addition to the information
listed in Instruction(s) 68. The CR10X keeps no
data from the sensor response.
Example: To send the command 1A0+2.3456-
87.654! where 1 is the SDI-12 sensor address,
+2.3456 is the value in Input Location 5 and -
87.654 is the value in Input Location 6, use the
following instructions:
01: SDI-12 Recorder (P105)
1:
1 SDI-12 Address
2: 0 Start Measurement (aM0!)
3: 1 Port
4: 5 Loc [ SendVal_1 ]
5: 1 Mult
6: 0 Offset
02: Extended Parameters 4 Digit (P68)
1:
65 Option ;ASCII character A
2: 48 Option ;ASCII character 0
3: 128 Option ;Send first value
4: 128 Option ;Send second value
5: 0 Option ;End of command string
6: 0 Option
7: 0 Option
8: 0 Option