Endress+Hauser OXY5500 - Page 58

OXY5500 Optical Oxygen Analyzer BA02195C
4
–28 Endress+Hauser
• Active alarm: In this mode, a negative value will be seen as 0% [ppm] O
2
.
An alarm signal “Forced Zero is active” is displayed at the top of the win-
dow. Refer to Figure 4–29. After rebooting the device, the default mode
“passive” is reactivated.
• Active stored: In this mode, a negative value will be seen as 0% [ppm] O
2
.
No alarm signal is displayed when the oxygen concentration reading is
negative. After rebooting the device, this mode remains active.
• Active with alarm stored: In this mode, a negative value will be seen as a
0% [ppm] O
2
. This mode combines the functionality of modes “active
alarm” and “active stored”. After rebooting this device, this mode remains
active.
The OXY5500 requires regular calibration as discussed in
“Calibrating the analyzer” on page 4-35. Negative oxygen
values which may be due to an inaccurate calibration are not
displayed when Forced Zero is active.
Once the Forced Zero feature is active, the reading as described
above applies to the main measurement screen and to the analog
4-20 mA output. Negative oxygen values are output as 4 mA.
ALARM
SIGNAL
Figure 4–29 Forced Zero alarm signal