Sensor and Controller Catalog

E xtended C apability

Lab Services

Quality Certification Lab (Continued)

Watlow certification verifies that the finished sensor complies with initial calibration tolerances as established by ASTM Standard E 230. This standard is based on the thermodynamic temperature scale of ITS 90. Initial sensor tolerances are susceptible to change during use due to environmental factors, including contamination, temperature, furnace gradient and physical abuse. Watlow’s advanced capabilities enable sensor calibration across a broad range of temperatures, from cryogenic -100 to 2300°F (-73 to 1260°C). ISO 10012 is the standard for all sensor and instrument calibration and results are traceable to the National Institute of Standards and Technology (NIST). Following are standard methods and specifications for sensor calibration:

Sensor x-rays verify the nonexistence of cracks at weld points that could let in humidity or gas and potentially shorten the life of the thermocouple.

• ASTM E207 • ASTM E220 • ASTM E230 • ASTM E644 • AMS 2750

Certification Testing Offered

Service

Description

Specifications

End-to-end calibration

Compares each end of a length of thermocouple wire, utilizing a common junction mea- surement test. This is a requirement to verify homogeneity requirements. Performance levels of wire insulations in the presence of high, local fields caused by electri- cal discharges. Routinely used in Watlow quality control testing. Verifies the sheath integrity in metal-sheathed cable and sensors to 1000 psi (70 kg/cm 2 ) in specially designed pressure chambers. Determines dimensions and detects and evaluates cracks, voids, inclusions and discontinuities. Technicians are qualified under SNT-TC-1A. Reveals the constituents and structures of metals. Photomicrographs are also available to determine and document average grain size and structure of prepared specimens.

ASTM E207, E220, E230

Dielectric testing

ASTM D149

Helium leak test

ASTM E235

Radiographic inspection

ASTM E94, E142

ASTM E3, E112, E235

Metallographic examination

Compaction density test

Determines compaction of insulating materials in metal-sheathed cable.

ASTM D2771

Drift test

Determines long-term stability and drift characteristics.

ASTM E601, E644

Thermal cycle test

Subjects individual sensors to repeated cycling through a temperature range.

ASTM E235

ASTM E780, E235, E644

Insulation resistance

Measures electrical insulation resistance properties between thermoelements and the sheath at ambient as well as elevated temperatures to determine presence of moisture or impurities, which could affect sensor performance.

15