KROHNE TTP 400 EN - Manual (Page 13)

Installation and Operating Instructions TTP x00 13
6 Product description
6.1 Applications
The screw-in temperature sensors of the series “with connection head“ are designed to measure
the temperature in all processes where high accuracy and ease of handling are what count. The
various mounting systems and adapters available enable the optimum choice to be made for your
application.
6.2 Functional principle
All temperature sensors of this series feature a Pt100 chip as the sensor element. A platinum
meander applied to a ceramic substrate is trimmed such that its electrical resistance at 0°C is
exactly 100 ohms. This resistance increases by 0.38 ohm for each 1 Kelvin temperature rise. The
exact resistance performance is described in the DIN EN 60751 standard. For our temperature
sensors we use without exception the high accuracy class “A“.
6.3 Construction
The various weldable process sleeves are made of stainless steel to allow installation in
conformity with hygiene requirements. Various evaluation modules are available for evaluation of
the Pt100 signal (see Accessories). A signal converter integrated into the stainless steel
connection head provides a 4...20-mA standardised signal locally, which can be transmitted noise-
free direct to the analogue input of an SPC or PLC. It is also possible to install a transmitter for
Profibus PA.
The Pt100 sensor is housed in a rugged 6 mm protective tube of variable length and made of
V4A. Due to the special type of thermal coupling, our temperature sensors achieve very fast
response times. Tapered sensor tips are also available for even higher requirements.
6.3.1 Pt100 resistance performance and wiring methods