Sigma Hellas Ltd contact information

If you still have problems, please let us know, by sending an email. Thank you!

Working Hours

Mon - Fri: 08:00 - 16:00 (EET)
Sat: Closed
Sun: Closed



Temperature is one of the most measured of the physical quantities, and as such correct measurement is very important. Temperature measurement can be divided in to two categories: contact and non-contact.

We offer temperature meters and controls for both contact and non-contact applications.

Contact Applications

There are two main types of technologies for measuring temperature - thermocouples and resistance thermometers. Sensors using these technologies can provide the ideal solution for most requirements.

Thermocouple systems are very versatile and can cover temperatures ranging from -250ºC to beyond 2000ºC; resistance thermometers provide greater precision, operating within the range -200ºC to 850ºC. Both methods have an output in the form of an electrical signal, which can be easily transmitted, switched, displayed, recorded and further processed using suitable data handling equipment.
Our range includes the following products and services

  • Pt1000 programmable temperature monitors/transmitters
  • Thermocouple assemblies
  • Platinum resistance thermometer assemblies
  • Swaged reduced tip temperature sensor assemblies
  • Miniature temperature sensor assemblies
  • Cables for thermocouples, resistance thermometry and instrumentation
  • Connector systems for thermocouple and resistance thermometry
  • Accessories for temperature measurement

Non-Contact Applications


The emissivity of a material (usually written ε or e) is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. A true black body would have an ε = 1 while any real object would have ε < 1. Emissivity is a dimensionless quantity.

Generally, the duller and blacker a material is, the closer its emissivity is to 1. The more reflective a material is, the lower its emissivity. Highly polished silver has an emissivity of about 0.02.

Examples of emissivity values applicable for material temperatures from 0 to 250°C
Aluminum polished

0.10 – 0.05

Aluminum Oxide 0.40 Ceramic 0.90 – 0.95 Foods 0.85 – 1.00 Paper 0.85 – 1.00
Steel Cold Rolled

0.70 – 0.90


0.10 – 0.40

Asbestos 0.95 Concrete 0.95 Gravel 0.90 – 0.95 Plastic 0.95 – 1.00 Steel Rough surface 0.95

0.10 – 0.30

Asphalt 0.90 – 1.00 Chromium 0.10 Gypsum 0.85 – 0.95 Steel Unoxidized 0.10 Carpet 0.85 – 1.00
Aluminum Anodized

0.60 – 0.95

Graphite 0.70 – 0.80 Electrical terminal blocks 0.60 Human Skin 0.99 Steel Oxidized 0.70 - 0.95

In many production and processing facilities, operations take place at high temperatures. Proper automation and quality control require safe detection and monitoring of temperatures without contact.

Infrared heat sensors absorb the heat radiation of objects and convert it into a switching signal. The advantage of having no mechanical contact between the object and the sensor makes infrared sensors idal for temperature monitoring applications, such as moving objects in spaces with difficult access, conductive or sticky objects/materials, surface treated objects, or on aggressive media where short responce times are required, dangerous applications for direct contact. Our range includes stand alone sensors & systems that can monitor temperature from a distance within the range of -20ºC to 2500ºC.