K320S-200 Remaining Useful Life Evaluation Routine (RULERŪ)


Test Method
The portable Remaining Useful Life Evaluation Routine (RULERŪ) instrument measures the oxidative resistance levels of mineral and synthetic hydrocarbon oils, ester-based and biodegradable oils. Utilizing voltammetric techniques, the RULERŪ quantitatively analyzes the relative concentrations of antioxidants in new and used oils in order to monitor the depletion rates of the antioxidant protection package in the oil. The RULERŪ can be used proactively in order to determine proper oil change intervals and to extend oil change intervals through timely antioxidant additive replenishments. In addition, the RULERŪ can be used to quantify antioxidant levels of incoming and stored oil supplies and to detect abnormal operating conditions prior to equipment failure signalled by abrupt antioxidant depletion rates.


Features and Benefits
• Patented electrochemical measurement technique

• Conforms to ASTM D6810 Method

• Compact and completely portable hand-held unit

• WindowsŪ CE-based simple touch screen operation

• Durable for use in harsh and industrial environments

• 320 x 240 pixel LCD backlit touch screen with automatic contrast

• Stores over 100 tests in memory

• Wireless infrared (IR) communication link to laptop and desktop computers

• Integrated charge status/low-battery indicator with intelligent fast charge

• Long-life lithium-ion battery with power backup


The RULERŪ Instrument
The patented RULERŪ technology is a portable oil analysis instrument that quickly measures the levels of antioxidants in petroleum- and synthetic-based oils, greases, and industrial fluids. Designed to provide rapid and accurate evaluations of lubricant oxidation stability and remaining antioxidant concentration, the RULERŪ is ideal for field testing, maintenance facilities, and oil analysis laboratories as part of a proactive oil condition monitoring program.

The Role of Antioxidants
The antioxidants added to lubricants are vital to fluid integrity and are specially formulated for each type of application, accounting for the various exposures to heat, atmospheric oxygen, and water. Under normal machine operating conditions, radical oxidation would typically degrade any lubricant without a protective additive package. This could result in sludge and deposit formation, filter blockages, oil thickening, and an increase in oil acidity. The antioxidants present in the additive package will significantly limit oil degradation from occurring but will be depleted in the process. Therefore, it is imperative to know the status of the antioxidants in oils being used in service.

Conventional Measurement Techniques
Many conventional laboratory techniques such as kinematic viscosity, total acid number (TAN), infrared (IR) data, and wear metal analysis are used for measuring the extent of oil degradation. These techniques only begin to show significant changes in the physical and chemical properties of the oils when a majority of the antioxidants have been depleted and the oil has begun to substantially degrade, approaching the end of its useful life. This is a point where machine wear and failure may become a severe problem. However, to ensure that a lubricant is not used past the end of its useful life, periodic oil changes are inherently conservative which results in discarding lubricant that is still suitable for use.

The RULERŪ Measurement Technology
The RULERŪ instrument quantitatively determines the remaining utility of the lubricant by measuring the remaining concentrations of the antioxidants. The rate of antioxidant depletion over time can be monitored and used to predict proper oil change intervals as well as detect abnormal equipment operation prior to machine breakdown. These important assessments can be easily made by field personnel from the data acquired and analyzed by the RULERŪ instrument. The results are then presented directly on the touch screen. In addition, the RULERŪ Data Management Software (R-DMSŪ) system, which is part of the RULERŪ package, enhances this monitoring process and can be utilized on a desktop or laptop computer.

The measurement principal of the RULERŪ is based upon linear voltammetry, where this patented electrochemistry technique can evaluate a wide range of antioxidants without any interference from water, fuel, soot, dirt, metal, silt, or other contaminants. The analysis of an oil sample requires the addition of less than 0.5 mL of oil to an electrolytic test solution and insertion of the RULERŪ probe into the solution. The instrument applies a voltage ramp across the three-electrode sensing system in the probe. At specific voltage values, the antioxidants will become chemically excited and create an oxidation current that is recorded by the instrument. A plot of oxidation current versus voltage, known as a voltammagram, is displayed on the touch screen. The results can then be readily analyzed using the RULERŪ instrument software and interpreted by the field operator to determine if any immediate maintenance action is necessary or to plan for the next appropriate oil change interval.

The RULERŪ Data Management Software (R-DMSŪ)
Utilizing the RULERŪ Data Management Software (R-DMSŪ) on a desktop or laptop computer, the resulting data for each test site can be easily tracked over time, enabling the user to identify normal trends for any given piece of equipment. Variations from these trends can be indicative of changes in system operating conditions causing the accelerated oxidation of the lubricant. The R-DMSŪ software package can maintain a large database of test results, display multiple test results, export data to other formats, and incorporate trending data from other techniques such as viscosity, acid number, infrared (IR) data, and wear metal analysis to provide a complete condition monitoring package. Therefore, with complete information about lubricant quality, determinations can be easily made regarding oil change intervals or additive reinforcement to extend the life of the lubricant.

The RULERŪ Test Solutions
The patented test solutions formulated specifically for RULERŪ analysis optimize the measurement of specific antioxidants in any given class of oils. These RULERŪ test solutions are provided in 7mL glass vials which attach easily to the RULERŪ test probe, have been identified by different colored caps, and are convenient for field and remote testing. Each vial contains 5mL of a specific test solution and 1g of specially prepared sand. After an oil sample is added to the test solution and the vial is shaken, the oil and debris will adhere to the sand and the antioxidants will remain in the solution for RULERŪ analysis. The shelf life of the RULERŪ solutions is at least one year from the date of manufacture.

The RULERŪ test solutions are available in four main classes: red, green, blue, and yellow. The red solutions have been designed for aviation oil applications, which includes ester-based turbine oils. The green solutions have been designed for general applications, which include phosphate ester-based oils, gear, compressor and hydraulic oils, greases, and transformer oils. The blue solutions have been designed for combustion engine applications, which include gear oils, gasoline and diesel crankcase oils, and marine oils. The yellow solutions have been designed for rust and oxidation applications, which include mineral-based steam and gas turbine oils, phosphate ester-based oils, gear oils, compressor and hydraulic oils, gasoline and diesel crankcase oils, marine oils, greases, and transformer oils.

Conforms to ASTM D6810

CE certified

Communication Ports
High-speed 4MBPS IrDA port on RULERŪ instrument
Standard RS-232 port on docking cradle

Operating Temperature Range
–30°C to +50°C
–22°F to +122°F

Power Supply
Rechargeable lithium-ion battery pack
Rechargeable lithium-manganese backup battery pack

Electrical Requirements
120V 50/60Hz
220V 50/60Hz

Included Accessories
Docking Cradle, Cable, and Communication Software
R-DMSŪ Software Package (RULERŪ Data Management Software)
Carrying Case for RULERŪ instrument and accessories (but does not accommodate docking cradle)
Micropipettor with disposable tips
Alcohol pads
Tissue Wipes
Instruction Manual

Dimensions lxwxh,in.(cm)
24.8x10.4x6.1 (9.75x4.1x2.4)
Net Weight: 1.9 lbs (0.85kg)

Shipping Information
Shipping Weight: 10 lbs (4.5kg)
Dimensions: 2 Cu. ft.

Ordering Information



Product Description

Electrical Requirements


RULERŪ Instrument

115V 50/60Hz


RULERŪ Instrument

220V 50/60Hz



RULERŪ Test Solutions - Vials
One case of RULERŪ test solution vials consists of 144 glass vials filled with 1g of sand and 5mL of the test solution. Choose from the following solutions based upon your application. Please contact Koehler Customer Service with any questions about ordering the test solutions.



Product Description


Red - Aviation Applications


Green - General Applications


Blue - Combustion Engine Applications


Yellow - Rust and Oxidation Applications


RULERŪ Test Solutions - Bottles
The RULERŪ test solutions are also available in 500mL bottles. Glass vials filled with 1g of sand are also needed to perform the proper analysis. Choose from the following solutions based upon your application. Please contact Koehler Customer Service with any questions about ordering the test solutions.



Product Description


Red - Aviation Applications


Green - General Applications


Blue - Combustion Engine Applications


Yellow - Rust and Oxidation Applications


Glass vials with sand (box of 100)


Additional Accessories



Product Description

Additional Information


Alcohol pads

1000 individually sealed pads


Tissue wipes

box of 300








Disposable 50ĩL micropipettor tips

pack of 250


Disposable 200ĩL micropipettor tips

pack of 250