Friday 20 January 2012

Temperature transmitter for safety applications

The new OPTITEMP TT 51 temperature transmitter, from Krohne, is developed with measurement accuracy, reliability, safety and user efficiency in mind according to a release from the company.

Constant measuring accuracy over a long period of time is crucial when it comes to monitoring process temperatures. The unit features a newly developed electronic system that boasts a long-term measuring error of ±0.1 °C (for Pt 100) or ±0.05 % of span. Over a period of five years, the long-term error is just a quarter of the drift of comparable temperature transmitters. By using the Sensor Matching feature, the total sensor/transmitter accuracy can be further increased.

The superior reliability of a measuring station equipped with this temperature transmitter can be attributed to more than one principle as the transmitter has double inputs for e.g. Pt 100 or Thermocouple sensors. The transmitter features SmartSense insulation monitoring to detect moisture in the measuring insert. If the measuring insert (and the sensor element) absorbs moisture, the electrical isolation resistance immediately decreases, resulting in a measurement error.

A second, redundant sensor can be connected to the OPTITEMP TT 51 transmitter by way of a dual input. The Sensor Backup function will reduce the risk of losing important measurements by automatically switching over to the back-up sensor in the unlikely event that the primary sensor fails.

For use in safety-related applications, it features SIL2 approval as per IEC 61508. The error monitoring and information meet the NAMUR NE 43, NE 89 and NE 107 recommendations. The transmitters are available with Ex-approvals according to ATEX. The EMC immunity meets Criteria A performance, based on EN 61326-1 and NAMUR NE 21.

The OPTITEMP TT 51 transmitter is programmable either directly from a PC via a USB interface or by means of any HART communication tool available on the market.  It may be mounted either directly inside a standard DIN B sensor head (head-mounted transmitter) or it is installed separately in a control cabinet as a space-efficient DIN- rail-mounted transmitter with a width of only 17,5 mm.

Krohne products are marketed in Ireland by DWN Instrumentation.

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