Radiation thermometers and thermocouples are available with a host of features to solve a wide range of application conditions. All infrared sensors are available in a wide range of wavelengths, temperature ranges and optical systems. Portable units almost always are available with carrying kits, and permanently mounted units are ruggedized. Listed below are other options, features and accessories that make these sensors more useful for certain types of applications.
Backlit LCD displays, integrally attached or remotely mounted from the thermometer, are available. Multiple variables can be viewed simultaneously on these displays. These data can include current temperature, minimum measured temperature (time based), maximum measured temperature (time based), average temperature measured (time based), and differential temperature (for example, between the target and the surroundings).
Microprocessor-based radiation thermometers have input options to allow data to be integrated into the measurement from other sensors or thermometers in the loop. For example, a separate thermocouple or RTD input to the thermometer can be used to compensate the measured target temperature for changing ambient temperature conditions.
Protection from high electromagnetic and radio frequency interference (EMI/RFI) is available if the thermometer must be installed in a difficult environments.
Most infrared thermometers can be supplied with an emissivity adjustment. In addition, some devices can be supplied with an adjustable field of view. This is accomplished by installing an iris in the optical system that can be opened or closed to provide wide or narrow angle field of views.
Handheld IR Thermometers
Handheld instruments are generally completely self-contained, battery-powered units, with manual controls and adjustments and some form of digital readout. Units can be mounted on tripods. Other accessories include:
Laser sights, which paint a visible spot on the target, making it easier to determine where the instrument is pointed. This option is available both integrally attached or detachable from the thermometer. Hand-held devices used for up-close spot temperature measurement (for example, to measure component temperature on printed circuit boards) can have audible focusing guides instead of light markers.
Dataloggers, for acquiring data from thermometers and recording it for future use;
Digital printers
Electrical system scanners, designed specifically for finding hot spots in electrical panels, switchgear, fuse panels, transformers, etc.
Handheld, shirt-pocket-size scanner for general surface temperature measurement.
Outputs: RS232C serial and/or 1 mV/degree.
Infrared Thermocouples
These self-powered devices generate a thermocouple signal output using radiated energy, but usually have no signal processing or display systems. An infrared thermocouple is a sensor only, but it does have a few options and accessories.
Cooling jacket kits for air or water cooling;
Handheld version for precise spot measurements;
Close-focus model with up to 60:1 field of view;
Periscope kit for right-angle measurements;
Low-cost (USD$99) model with ABS plastic housing;
Adjustable emissivity;
Two-color pyrometry unit that uses short-wave and long-wave infrared thermocouples.
Fiber Optic Sensors
Probes are available in lens cells of various sizes, with replaceable glass or quartz tips. Options include a ceramic/metal tip for high temperatures, a polymer bolt for extrusion applications, ejector pin probe for injection molding, and right angle prisms. Sensor probes also are available as optical rods up to 60 cm long.
Cables can be supplied in single, bifurcated or trifurcated fiber optic bundles, and enclosed in jackets made of flexible stainless steel (standard), ceramic, heavy duty wire braid for abrasion resistance, or Teflon for high radio frequency fields. Cables typically are up to 30 ft long.
Indicators and Controllers
Display units and controllers are available in models ranging from a simple digital panel meter that displays the signal as a temperature in °F or °C, to complex multi-channel processors that perform signal conditioning, linearization, peak-picking, alarm monitoring, saving min/max values, signal averaging, data logging and a host of other signal processing and manipulation functions.
Mounted IR Thermometers
The same basic features, options and accessories are available for radiation thermometers, two-color systems, and line scanners. Ruggedized for use on the plant floor, all these devices have several accessories to help them survive in hostile environments.
Air purge--Attaches to front end of sensor housing and provides positive air pressure in front of the lens, preventing dust, smoke, moisture and other contamination from reaching lens. In two-color systems, it can attach to front of re-imaging lens.
Air or water cooling jackets--Available for warm (35°F above ambient) and hot (up to 400 °F) environments, cooling jackets keep sensor temperature at normal levels inside the enclosure.
Peltier effect cooling--Some line scanners have electronic cooling systems, using Peltier effect devices.
Sighting accessories, including sight tubes, laser pointing devices, and scopes.
Onboard data logging functions are available, as well as options for thermal printers to retrieve stored data. Data can also be remotely transmitted digitally.
Transmitters--Ruggedized NEMA 4 housing with 4-20 mAdc and/or RS232C/RS485 outputs.
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