YSI 550A
Y S I
Environmental
Page 1
GENERAL DESCRIPTION
The YSI 550A Handheld Dissolved Oxygen Instrument is a rugged, microprocessor based, digital
instrument with a field-replaceable YSI dissolved oxygen probe. The YSI 550A DO Instrument is
impact-resistant and waterproof.
The YSI 550A DO Instrument is designed for field use and is available with cable lengths of 12, 25, 50,
or 100 feet (3.5, 7.5, 15, 30.5 meters). The body of the probe has been manufactured with stainless steel
to add rugged durability and sinking weight. The large Liquid Crystal Display (LCD) is easy to read
and is equipped with a backlight for use in dark or poorly lighted areas.
The YSI 550A DO Instrument can be easily calibrated with the press of a few keys. Additionally, the
instrument’s microprocessor performs a self-diagnostic routine each time the instrument is turned on.
The self-diagnostic routine provides you with useful information about the function of the instrument
circuitry and the quality of the readings you obtain.
The system displays temperature in either
o
C or
o
F and dissolved oxygen in either mg/L (milligrams per
liter) or % air saturation. The system requires only a single calibration regardless of which dissolved
oxygen display is used, and will calibrate in either mode. Salinity compensation values can be changed
at any time without performing a new calibration.
A detachable calibration chamber is mounted to the back of the instrument. A small sponge in the
chamber can be moistened to provide a water saturated air environment that is ideal for air calibration.
This chamber is also designed for transporting and storing the probe. When the probe is stored in the
chamber, the moist environment will prolong effective membrane performance and probe life.
The YSI 550A DO Instrument is powered by 4 C-size alkaline batteries. A new set of alkaline batteries
will provide approximately 2000 hours of continuous operation. If the backlight is used often, batteries
will be depleted faster.
The YSI 550A case is waterproof with an IP-67 rating. The instrument is 100% corrosion proof and can
be operated in a wet environment without damage to the instrument.
INITIAL INSPECTION
When you unpack your new YSI 550A DO Handheld Instrument for the first time, check the packing
list to make sure you have received everything. If there is anything missing or damaged, call the dealer
from whom you purchased the YSI 550A. If you do not know which authorized dealer sold the system
to you, call YSI Customer Service at 800-897-4151 or 937-767-7241.
