36
MODEL SOLU COMP II
SECTION 6.0
CALIBRATION
6.3.2 Procedure — Zeroing the sensor.
1. Place the sensor in the zero standard. Be sure no air bubbles are trapped against the membrane. The sensor
current will drop rapidly at first and then gradually reach a stable zero value. To monitor the sensor current, go
to the main display and press
until the sensor input current is showing. Typical zero current for an ozone
sensor is -10 to +10 nA.
A new sensor or a sensor in which the electrolyte solution has been replaced may require several hours (occa-
sionally as long as overnight) to reach a minimum zero current. DO NOT START THE ZERO ROUTINE UNTIL
THE SENSOR HAS BEEN IN ZERO SOLUTION FOR AT LEAST TWO HOURS.
2. Press MENU. The main menu screen appears. Choose
Calibrate
.
3. Choose
Measurement
.
4. Choose
Zero
.
5. The screen at left appears. The top line is the current ozone reading
based on the previous calibration or, for a first time calibration, the default
sensitivity.
6. Once the reading is stable, the screen at left appears. Sensor zero is
complete and the analyzer has stored the zero current. The screen
remains until the operator presses MENU then EXIT to return to the main
display.
NOTE
Pressing ENTER during the zero step will cause the analyz-
er to use the present sensor current as the zero current. If the
sensor is zeroed before the current has reached a minimum
stable value, subsequent readings will be in error.
After zeroing, leave the sensor in the zero solution and verify that the sen-
sor current is between -10 and +10 nA. To display the sensor current, go
the the main display and press until the input current is showing.
7. This screen appears if the zero current is extremely high. See Section 8.3
for troubleshooting. To repeat the zero step, press EXIT and choose
Zero
.
8.
This screen appears if the zero current is moderately high. To continue,
choose
Yes
. To repeat the zero step, choose
No
. See Section 8.3 for
troubleshooting.
C
Ca
al
li
ib
br
ra
at
te
e
Hold
Program
Display
CalSensor1?
M
Me
ea
as
su
ur
re
em
me
en
nt
t
Temp
S1 Live
1.000ppm
Zeroing
W
Wa
ai
it
t
Sensor Zero Fail
Current Too High
S1 Live
0.000ppm
Sensor Zero Done
Cal S1?
InProcess
Z
Ze
er
ro
o
Possible ZeroErr
Proceed?
Yes
N
No
o