Metis MQ11 and MQ22
Two-Color Pyrometer

Two-Color- or Ratio- Pyrometers are typical names for pyrometers which measure temperatures from the ratio of radiation signals of two adjacent wavelengths as opposed to measuring the absolute intensity like single wavelength units do. The advantages for customers are the following:

• Gray bodies, i.e., targets with the same emissivity on both wavelengths, can be measured without emissivity setting.
• There is automatic compensation for dust, smoke or a dirty viewing window between pyrometer and target.
• Temperature errors are minimized if the target is too small or moving and the field of measurement can’t be completely covered.

Metis Two-Color Pyrometers have universal applications, which means that they can also be used as two-color pyrometers as well as single wavelength pyrometers. In single wavelength mode, customers have the choice of deriving the analog output signal from shorter or longer wavelengths, or both. Using digital communication these temperature measurement results can be recorded and compared, to determine quickly whether the target is a „gray body“ radiator or not.

Lenses and Fiber-Optic Cable: The infrared energy radiated by the target is transferred via focusable lenses either directly on the detector (standard version) or on one end of a fiber optic cable. For installations with limited space, there is a fixed-focus miniature version. This feature offers the advantage of measuring the smallest spot (focused) or the average temperature of a bigger spot (out of focus) for the particular distance. For applications with need for refocusing the lens during operation, a remote focusable optics is available. If additional windows are necessary, they must offer similar optical characteristics. Lenses are made of BK7 (quartz glass), an optical glass which is highly transparent within the spectral range of Metis MQ11.

The detector is sensitive to infrared radiation in an area called the cone of vision. For the spot size diameter Ø of this area at the shortest, medium and widest distances, when focused, please refer to Chart 2. The cone of vision diameter in front of the lens is max. 20 mm. This changes continuously in relation to the spot size diameter given in the chart. This area has to be kept free from any intervening objects. The spot size diameter for distances not given in the chart can be calculated by interpolation.

The spot size of the focusable lenses to be used with the Metis MQ Fiber-Optic version can be taken from Charts 3 and 4. The larger lens tube diameter of 25 mm offers the advantage of a smaller spot at the same distance. Fiber-optic versions are supplied with 2.5 m, single mode fibers, having a diameter of 0.2 mm, (0.4 mm zero scale 300°C or 600°C only). Longer cables with up to 20 m are available on request

Download Metis MQ11 and MQ22 Two-Color Pyrometer technical specifications