RayTek FR, FA Product Description, Theory of Operation for 2‐Color Sensors, Models

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Product Description

2 Product Description

The Marathon FA/FR fiber optic series of instruments are high‐performance infrared thermometers. Each has a front end consisting of a small, fixed focus optical head coupled to a rugged fiber optic cable wrapped with a flexible stainless steel sheath. The fiber optic cable attaches to an electronics enclosure, which can be mounted away from the hot, hostile environment. The electronics enclosure can be connected to a computer with its two‐way RS485 interface.

Temperature measurements can be taken using either of the following modes:

1‐color mode (FA and FR sensors) – for standard temperature measurements. The 1‐color mode is best for measuring the temperature of targets in areas where no sighting obstructions, either solid or gaseous, exist. The 1‐color mode is also best where the target completely fills the measurement spot and where the background or foreground are higher in temperature than the target.

2‐color mode (FR sensors only) – temperatures are determined from the ratio of two separate and overlapping infrared bands. The 2‐color mode is best for measuring the temperature of targets that are partially obscured (either intermittently or permanently) by other objects, openings, screens, or viewing windows that reduce energy, and by dirt, smoke, or steam in the atmosphere. The 2‐color mode can also be used on targets that do not completely fill the measurement spot, provided the background is much cooler than the target.

Each model operates as a temperature measurement subsystem consisting of optical elements, spectral filters, detector, and digital electronics. All components are water‐tight NEMA‐4 (IEC 529, IP 65) rated and are built to operate on a 100 percent duty cycle in industrial environments. Simultaneous analog and digital outputs consist of standardized current signals commonly available for use with computers, controllers, recorders, alarms, or A/D interfaces.

Model

Description

FA1A, FA1B, FA1C

1-color-sensor in spectral range of 1 µm

 

different temperature ranges

FA1G

1-color-sensor specifically designed for measuring glass

FA2A, FA2B

1-color-sensor in spectral range of 1.6 µm

 

different temperature ranges

FR1A, FR1B, FR1C

2-color-sensor in spectral range of 1 µm (nominal)

 

different temperature ranges

 

Table 1: Models

2.1 Theory of Operation for 2‐Color Sensors

Two‐color ratio technology makes possible accurate and repeatable temperature measurements that are free from dependence on absolute radiated energy values. In use, a 2‐color sensor determines temperature from the ratio of the radiated energies in two separate wavelength bands (colors). The benefits of 2‐color sensors are that accurate measurements can be made under the following conditions:

When the field of view to the target is partially blocked or obscured.

When the target is smaller than the sensor’s field of view.

When target emissivities are low or changing by the same factor in both wavelength bands.

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Marathon Series FA/FR

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Contents Marathon FA/FR Series Page Worldwide Headquarters Fluke Service CenterContacts European Headquarters France United KingdomWarranty Table of Contents Milliamp Output Relay Outputs Trigger Fiber Calibration Page Safety Instructions Safety InstructionsMarathon Series FA/FR Theory of Operation for 2‐Color Sensors Product DescriptionProduct Description ModelsTargets Smaller Than Field of View Partially Obscured TargetsLow or Changing Emissivities Measurement Specifications Technical DataTechnical Data FA ModelsGeneral Specifications Electrical Specifications Dimensions Dimensions of Optical HeadFA ModelsAdjustable Mounting Bracket for Optical Head Optical Specifications Standard FocusClose Focus Spot Size Charts for FA models Close FocusStandard Focus Spot Size Charts for FR models Close Focus Spot Size Charts for FR models Scope of DeliverySensor Location Sensor LocationSensor Placement 1‐Color Mode Sensor Placement 2‐Color ModeSensor Placement in 2‐Color Mode Viewing AnglesAcceptable Sensor Viewing Angles Installation InstallationMounting the Sensor Aiming Fiber Optic CableInstalling the Electronics Housing Configuring the Sensor CableRemoving the Terminal Block Connecting to a PC Power SupplyRS232/485 Interface Converter Multidrop Installation 4‐Wire Multidrop Installation 2‐WireConnecting to Terminal Block Wiring for 2‐Wire Sensor SetupWiring Installing of Multiple Sensors in a NetworkAddressing Operation OperationControl Panel Mode Selector Button Sequence FA Models Operation ModesEmissivity 1‐Color Temperature DisplaySlope 2‐Color Peak Hold PKH 4 2C/1C SwitchAveraging AVG Valley Hold VAL Overview to Hold FunctionsDeadband SetpointsHold Functions Milliamp Output Ambient Background Temperature Compensation FA ModelsInputs and Outputs Relay OutputsFactory Defaults Factory DefaultsOptions Cooling Platform for Electronics HousingOptions Accessories selection AccessoriesAccessories OverviewAir Purge Collar Protection TubeFitting System Flexible Fitting SystemOrder number Model Available RS232/485 Interface ConvertersIndustrial Power Supply Dimension of Industrial Power SupplyProgramming Guide Command StructureProgramming Guide Remote versus Manual ConsiderationsBurst Mode Poll ModeTransfer Modes Response Time in Setup Mode = + n ⋅15000Command List Command ListXUFR1A Command Examples Command ExamplesTroubleshooting Minor Problems MaintenanceMaintenance TroubleshootingError Codes in 2‐Color Mode FR models Error Codes in 1‐Color Mode FA modelsFail‐Safe Operation Current Output Values in accordance to an Error Examples of failsafe conditionsCleaning the Lens Removing the Fiber Optic Cable Replacing the Fiber Optic CableRemoving the Fiber Optic Cable from the Optical Head Put cable out Mounting the Fiber Optic Cable Attaching the Fiber Optic Cable to the Optical HeadFiber Calibration Dialog for the Calibration of the Fiber Cable Determination of Emissivity AppendixAppendix Typical Emissivity ValuesTypical Emissivity Values Metals Marathon Series FA/FR55Typical Emissivity Values Non‐Metals How to determine slope? Typical SlopesSignal Reduction FR Models Typical Percentage of Allowed Signal Reduction FR1A ModelsMaximum Error Attenuation Influence on AccuracyMarathon Instrument Calibration