Xylem H-3531 FlashLite - Manual (Page 40)

5-2 SDI-12 Command and Response Protocol
H-3531
5.1 Measure Command
The Measure Command causes a new measurement sequence to be executed. Data values
generated in response to this command are stored in the sensor's buffer for subsequent collection
using "D" commands. The data will be retained in the sensor until another "M", " C", or "V"
command is executed.
Command Response Description
"aM!" "atttn" Initiate measurement
"aM1!" "atttn" Initiate measurement
Where:
a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
M is an upper-case ASCII character
ttt is a three digit integer (000-999) specifying the maximum time, in seconds,
the sensor will take to complete the command and have measurement data
available in its buffer.
n is a single digit integer (0-9) specifying the number of values that will be
placed in the data buffer. If "n" is zero (0), no data will be available using
subsequent "D" commands.
Upon completion of the measurement, a service request "a" is sent to the data recorder
indicating the sensor data is ready. The data recorder may wake the sensor with a break and
collect the data any time after the service request is received or the specified processing time has
elapsed.
Example of a H-3531 "aM!" command:
Command
Response Time Values Description
"aM!" "a0064" 6 sec 4 Make measurement
Subsequent Command Response
"aD0" a+AA.AA+BB.BBBB+CC.C+DD.D
Where:
AA.AA = Stage (feet, inches, meters etc.)
BB.BBBB = Pressure (PSI)
CC.C = Temperature (C)
DD.D = Power Supply Voltage (Volts)