Measurement Specialties
KPSI
®
Digital Series User’s Manual
Page 13
www.Meas-Spec.com
Depending on the variation of the command, the sensor will reply with one of these response
formats:
av
avu
avvv
Where “a” is the
address
, “v” is a
data value
, and “u” is an optional
units
indicator.
Both “v” and “u” have the format of a polarity sign (+ or -) followed by up to seven
digits, including a decimal point. Format returned depends on the command variation.
measurement command variations
To enhance the error detection capability in SDI-12 data collection systems, variations of the
Start Non-Concurrent Measurement
commands (
M
,
M1
...
M9
) and
Start Concurrent
Measurement
commands
(C
,
C1
, ...
C9
) are available. One variation requests that the data be
returned with a 16-bit
Cyclic Redundancy Check (CRC)
appended. It adds a
“C”
to
command, such as
MC
,
MC1
,
CC
, or
CC1
The number of measurements returned in response
is the same as the measurements returned for a
non-CRC
command, but with a CRC
appendage following them.
An example of such a command follows:
aMC!
Where “a” is the address character, “M” is a basic command to make a
measurement, and “C” is the added command letter requesting a CRC appendage.
The sensor might respond with:
a0053
Acknowledging it is at address “a” and indicating that after 5 seconds, three (3)
measurements will be ready to read with “
D0
” command.
When an “M”command measurement is complete, the sensor responds with an extra
Service
Request
response.
a
Where “a” is the address character.
