YSI Incorporated
YSI 550 DO Handheld Instrument
12
SECTION 4 CALIBRATION
Dissolved oxygen calibration must be done in an environment with a known oxygen content.
Since the amount of oxygen in the atmosphere is known, it makes an excellent environment for
calibration (at 100% relative humidity). The calibration/storage chamber contains a sponge to
create a 100% water saturated air environment.
4.1 BEFORE YOU CALIBRATE
Before you calibrate the YSI 550 DO Instrument complete the procedures discussed in Section 2,
Preparing the YSI 550 and Section 3, Preparing the Probe. You can calibrate the YSI 550 DO
Instrument in either mg/L or % saturation. In the section below, you will find instructions on how to
calibrate and change between these modes.
Note: While testing to EN-61000-4-6, Conducted RF Immunity, per Table A.1 of EN61326,
Electrical Equipment for Measurement, Control and Laboratory Use, the YSI 550 exhibited an
ERROR 8 message from 8.6 MHz 22.8 MHz at induced RF voltages of 3-Volts to 1-Volt RMS on
the 25-foot probe cable. If you observe this interference please relocate the probe-cable away from
heavy industrial equipment power and control cables or communications equipment cables which
may be causing the interference.
To accurately calibrate the YSI 550, you will need to know the following information:
!
The approximate salinity of the water you will be analyzing. Fresh water has a salinity of
approximately zero. Seawater has a salinity of approximately 35 parts per thousand (ppt). If you
are uncertain what the salinity of the sample water, use a YSI 30 Salinity-Conductivity-
Temperature instrument to determine salinity.
!
IF you are going to calibrate in % saturation mode, you need to know the approximate altitude
of the region where you are located.
4.2 THE CALIBRATION PROCESS
1.
Ensure that the sponge inside the instrument's calibration chamber is moist. Insert the probe
into the calibration chamber.
2.
Turn the instrument on by pressing the ON/OFF button on the front of the instrument. Wait
for the dissolved oxygen and temperature readings to stabilize (usually 15 minutes is required
after turning the instrument on).
3.
To enter the calibration menu, use two fingers to press and release both the UP ARROW and
DOWN ARROW keys at the same time.
Summary of Contents for 550 DO
Page 1: ...YSI 550 Handheld Dissolved Oxygen and Temperature System Operations Manual ...
Page 2: ......
Page 4: ...ii ...
