Introduction
The document discusses the challenges and solutions for non-contact temperature measurement of metal sheets at low temperatures, focusing on the use of pyrometers.

Specifications
For measuring metal sheets starting at room temperature, long-wave pyrometers with a spectral sensitivity of 8-14 µm are recommended. However, for temperatures starting at 75 °C, shortwave devices with a wavelength of approximately 2.4 µm are preferred due to their higher sensitivity and reduced pollution sensitivity.

Challenges
1. Low thermal radiation and special radiation properties of metals make measurement challenging.
2. Longwave pyrometers capture more reflecting radiation than the actual sheet temperature.
3. Shortwave pyrometers are sensitive to interfering radiation from artificial light or sunlight, especially below 150 °C.

Solutions
1. Use shadowing measures to protect against extraneous light for temperatures up to 150 °C.
2. In coil gaps, multiple reflections improve emissivity, allowing better temperature measurement.
3. Use pyrometers with high optical resolution and laser sighting for accurate measurement in coil gaps.

Measurement Systems
Two pyrometer models are discussed:

• PA 10 AF 1/L: Measuring range 0-1000 °C, spectral range 8-14 µm.
• PA 28 AF 10/L: Measuring range 75-650 °C, spectral range 1.8-2.4 µm.

Both models have specific response times and require a 24 V DC power supply.

Mounting Assemblies
Two mounting assemblies are detailed, each consisting of components like dust stops, cooling jackets, and oscillating mirrors to ensure optimal measurement conditions.

Contact Information
Contact details for Keller HCW GmbH and its international sales and service centers in China, France, India, and Russia are provided.