Type / No.
Rev.
Date
Page
Total pages
EW082.695_en
5
02 August 2010
16
28
EsiWelma
s.r.l.
Two successive steps are required for calibration:
•
Calibrating the zero point (
clean air for toxic and flammable gas, nitrogen for poison
gas such as CO
2
)
•
Calibrating the factory-set concentration (default: 50% LEL for explosive gases, 500
PPM for CO, 5000 PPM for CO
2
, 4%vol for O
2
) as per the section above
At this point it is possible to press:
•
ESCAPE to take the sensor back to normal operation
•
ENTER to start up calibration of 0 (zero) set point in clean air (zero gas
concentration)
When the words In progress… show on the display, wait until the end of the procedure
At the end, if the calibrating procedure has been successful the display will show:
The top two lines stay the same, the third line shows:
0XXX= Steps of the A/D converter to read the sensing element.
The next line:
SSS = Steps applied to the electronic potentiometer (only for sensors that include this)
VVVV = Value read by the converter and expressed in steps, not in concentration
measuring unit.
The two values could be periodically updated throughout the procedure that can last for
many seconds (duration depends on the type of sensor).
At this point it is possible to press:
•
ESCAPE to take the sensor back to normal operation
•
ENTER to start up calibration at the default gas concentration (2
nd
set point)
If Zero calibration was not successful, the display will show Fail. Press ENTER to repeat the
zero calibration procedure.
If Zero calibration was successful, when ENTER is pressed, calibration at the default set
point will start up. The display will show:
S e n s o r :
T T T T T T T
C a l i b r a t i o n P o i n t
0
P = 0 X X X
I n p r o g r e s s . . .
Fig. 4.14
S e n s o r :
T T T T T T T
C a l i b r a t i o n P o i n t
0
P = 0 X X X
O k : b = S S S t = V V V V
Fig. 4.15
S e n s o r :
T T T T T T T
C a l i b r a t i o n I I P o i n t
P = 0 X X X
Fig. 4.16
