Envco – Environmental Equipment

The YSI Model 55 Handheld Dissolved Oxygen System is a rugged, micro-processor based, digital meter with an attached YSI dissolved oxygen probe. Dissolved oxygen readings are automatically compensated for temperature. Also available is the YSI 55D with a detachable cable.

• Probe is weighted for quick sinking
• Large, easy-to-read backlit display
• Cables are available in 12, 25, or 50 feet lengths (3.7, 7.6 and 15.2m)
• Meets IP-65 water tightness requirements
• Low-battery indicator on the display
• CE compliant version

The YSI Model 55 is designed for field use and is available with cable lengths of 12, 25 or 50 feet. 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 back-light for use in dark or poorly lighted areas.

The Model 55's micro-processor allows the system to be easily calibrated with the press of a few keys. Additionally, the micro-processor 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 simultaneously displays temperature in oC 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 you use. You can switch back and forth from % air saturation to mg/L with a single push of the MODE key.

A calibration chamber is built into the instrument. A small sponge in the chamber can be moistened to provide a water saturated air environment which 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 instrument is powered by six AA-size alkaline batteries. A new set of alkaline batteries will provide approximately 100 hours of continuous operation. When batteries need to be replaced, the LCD will display a "LO BAT" message.

The YSI Model 55 instrument case is splash resistant. You can operate your Model 55 in a steady rain without damage to the instrument.

Ordering Information
Model 55 DO Meter
55-12 55 DO Meter with 12 ft. cable
55-25 55 DO Meter with 25 ft. cable
55-50 55 DO Meter with 50 ft. cable

Model 55 “D” DO Meter
55D 55 DO Meter with Detachable cable connection
55D-12 DO/Temp Probe with Detachable 12 ft. cable
55D-25 DO/Temp Probe with Detachable 25 ft. cable
55D-50 DO/Temp Probe with Detachable 50 ft. cable