The T32 is the flagship of WIKA’s temperature transmitters – and a bestseller, too: The instrument of serial number 1000000 has already undergone manufacturing.
As one of the first temperature transmitters worldwide, T32 has complied with all requirements of the standard for functional safety to IEC-61508, also known as SIL (Safety Integrity Level). The WIKA in-house development was certified as part of a full assessment by TÜV Rheinland as independent body.
For successful SIL certification, the development process for T32 had to follow exactly the V model of IEC-61508. In addition, it was mandatory to implement an extensive diagnostic functionality for detecting critical error states in instrument operation. It allows the plant manager to bring his process to a safe state in case of malfunction. The function comprises, among other things, monitoring the sensor lead resistances, sensor monitoring, continuous microcontroller self-diagnostics, and hardware monitoring. The functionality is rounded off by very good long-term stability and excellent EMC characteristics.
The development process required for SIL certification in accordance with the V model was consistently implemented at WIKA for the first time as part of the T32 project. Compared with conventional product development, the standard requires much higher documentation and product validation expenditure.
Excellent quality figures
In retrospect, this additional expenditure has paid off by giving excellent quality figures: For the SIL generation of the T32 (the third overall), for years the return ratio has been in the single-figure ppm range. Its longstanding and worldwide proven reliability even in demanding industrial environments, for example extreme cold of -50 °C, very high humidity of more than 90 per cent or strong vibrations, have impressed our customers.
The experience made with other SIL developments such as the pressure transducer TIS-20 has confirmed it: Consistent implementation of the development process benefits product quality.
Further information on the temperature transmitter T32 can be found on the WIKA website.