YSI Model 550A

Handheld DO Meter

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The YSI 550A handheld DO meter is a highly rugged, accurate, and easy to use field DO meter. It features an extended range of 0 to 500 % air saturation or 0 to 50 mg/L. Accuracy and reliability are maintained with YSI’s polarographic DO probe, which is field replaceable removing the need to send in an entire instrument or cable for DO probe replacement. Automatic temperature compensation is provided by a built in temperature sensor utilitizing YSI’s temperature precision thermistor, and manual salinity inputs are automatically calculated into the reading. Calibration is easily and accurately performed using the built in calibration/probe storage chamber and altitude adjustments.

YSI’s new handheld DO meter, the Pro20, is the suggested replacement for the YSI 550A.

The YSI 550A is easy to use and features a large, backlit, LCD display that simultaneously displays both DO measurements and temperature. The probes are weighted, durable, and feature screw on cap style polyethelyne membranes for quick and easy replacements. The polyethylene cap style membranes allow for faster response times and require less flow. the cables are built into the unit itself with the probe being field replaceable, allowing many malfunctions to be quickly handled by a simply changing out the DO module. The instrument is powered by 4 C alkaline batteries and has a runtime of up to 2000 hours.

YSI also manufacturers the economical EcoSense DO200 and the new ProODO optical DO meter. Both feature detachable cables and the ability to switch from field DO cables to lab BOD cables by simply swapping the cable.

One of the most durable field DO meters, the YSI 550A is IP67 rated waterproof and is constructed from high impact resistant plastics. Durability, combined with easy to replace membranes and end user replaceable DO modules provides for a long service life and low cost of ownership. The YSI 550A is available with built in cables ranging from 12 to 100 feet. Every instrument includes a probe, batteries, and a replacement membrane kit making them immediately ready to calibrate and put to use.

YSI 550A Features

• Large range, 0 to 500% air saturation or 0 to 50 mg/L
• Measures and calibrates in either % air saturation or mg/L
• Automatic temperature compensation
• Automatic compensation for an user input salinity value
• Polyethylene membranes reduce both response times and flow dependency
• Easy calibration with altitude corrections
• Easy to change, cap style membranes
• End user replaceable DO module saves on maintenance
• 2000 hour runtime from one set of batteries
• Rugged IP67 waterproof casing
• Available with cable lengths up to 100′

YSI Model 550A Handheld DO Meter

Call to Order
1-888-234-5678

• 1 Includes: YSI 550A with attached cable, DO probe, p/n 605306 cap membrane kit, 4 C alkaline batteries, and a user manual
• 2 Carrying case is p/n 655100 soft sided case

YSI Model 550A Replacement DO Membranes and Probe

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1-888-234-5678

• 1 Includes: 6 screw on cap membranes, sanding disk, electrolyte solution, and instructions
• 2 Includes: replacement do module, tool, and instructions

YSI Model 550A Accessories

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1-888-234-5678

• 1 Allows securing the instrument to a desk, boat, etc...
• 2 Allows the instrument to stand on any flat surface