Specifications
Instruction Manual    Alpha DO 500 
16 
  NOTE: The transmitter proceeds to the second point of calibration if the 
displayed reading is less than 10% of the high-point value. 
NOTE: The transmitter does not accept the calibration and shows 
calibration error if the displayed (measured) value is more than 10% of 
the high-point value. 
4
If the low-point calibration is successful, the Transmitter proceeds to the 
second point. The lower display shows ‘HI’. Take the electrode out of low 
oxygen solution and immerse it in a higher dissolved oxygen 
concentration (8.24 mg/l) solution. 
The upper display shows the measured value of dissolved oxygen of the 
solution. Allow the reading to stabilize. LCD shows ‘READY’ annunciator 
when the reading is stable. 
Press  or  key to adjust the reading to 8.24 mg/l. The Transmitter 
allows adjusting up to r50% of the measured value. 
Press ENT key to confirm the reading. 
NOTE: 
The transmitter does not accept the calibration and shows 
calibration error if the displayed (measured) value is more than 
50% of the high-point value. 
55
The calibration is completed. The DO Transmitter reverts to 
measurement mode. 
NOTES: 
x  If the displayed value is more than r10% of the high-point value, the 
Transmitter indicates a calibration error by showing ‘ERR’ and blinking 
electrode 
 annunciator. If this happens, press  and  keys together 
to return to measurement mode. Restart the calibration from Step1. 
x  To exit from calibration mode without confirming calibration, press  
and  keys together. 
x When calibrating with manual temperature compensation, the 
Transmitter automatically changes from preset ‘process temperature’ to 
‘calibration temperature’. After leaving calibration mode, the transmitter 
switches back to the ‘process temperature’. (Refer section 5.4 for 
temperature settings) 










