Delta OHM PMBsense-A, Operating Manual

Page: 14 / 24

PM[B]sense
- 14 -
V1.3
CO
2
calibration (only PMBsense…):
A 2-point (CO21 and CO22 commands) or 1-point calibration (CO2O command) can
be performed. The points are chosen by the user. To perform the calibration, the
transmitter must be placed in an environment with a known CO
2
concentration.
While the 2-point calibration allows moving the two calibration points independently,
and therefore also to adjust the slope of the sensor response curve, the 1-point cali-
bration simply adds an offset to the measurement (the two calibration points are
shifted of the same amount) and is typically accomplished by placing the transmitter
in clean air.
Before performing the calibration, the type of calibration to be used must be set to
“user” with the CC command.
The transmitter allows manually setting, with the DA command, a string that is saved
as the date and time of the calibration. The string must be set before performing the
calibration.
Command Reply Description
CO21n & t| CO
2
calibration in the first point at n ppm.
The transmitter must first be placed in an environment
with a known CO
2
concentration (the value n entered in
the command).
The value t in the reply to the command indicates the
number of seconds required for the transmitter to com-
plete the calibration operation. During this time, the
transmitter sends strings notifying the progress of the
operation; for example:
“CO2 calib. Status:IN PROGRESS 8% Avg:1096ppm Dev:0ppm”
At the end, the OK 100% notification indicates that the
operation was successful; for example:
“CO2 calib. Status:OK 100% Avg:1100ppm Dev:7ppm”
CO22n & t| CO
2
calibration in the second point at n ppm.
Operation similar to the CO21command.
CO2On & t| CO
2
calibration at n ppm (1-point calibration – offset ad-
justment).
Operation similar to the CO21command.
DAyyyy/mm/dd
hh:mm:ss &| Saves the string “aaaa/mm/gg hh:mm:ss” as the date
and time when calibration is performed.
The command must be sent before performing the cali-
bration.
GA & yyyy/mm/dd
hh:mm:ss Reads the date and time saved with the DA command.
CCn &| Sets the type of calibration to be used:

User if n=0

Factory if n=1
Default : Factory (n=1)
CO2D &| Reset of user calibration.
Restoring the factory configuration:
Command Reply Description
DFLT &| Restores the factory configuration.