Temperature sensors - Technology and application
Functionality
The compact
models TN 552 GPP and TN 552/1 GPP have two independent adjustable switching
points. The compact models TN 552 GAPP and TN 552/1 GAPP have one independent
adjustable switching point and one scalable 4...20 mA analog output.
The
detecting range for fluids is from – 40 °C to +120 °C, the tolerance is 0.3 °C
(0...80 °C).
The compact
models TN 552... offer a window function as an alternative to the standard
limit monitoring. Additionally, the NO/NC output function is programmable.
Transient temperature changes can be bridget with a switch-on / switch-off time
delay.
The
push-buttons on the front of the sensor are used for programming the sensor
functions. The programmed switching point and parameters are displayed and set
by keyboard request. This function is possible while the sensor is measuring.
Temperature
sensor with threaded sleeve allowing for
exchange during ongoing operations
The
temperature sensor TN 553 can easily be exchanged during ongoing operations.
This is made possible through the use of a special stainless steel (AISI 316
Ti) threaded sleeve that is mounted in the tank or pipe. In this way the
compact device can at any time be removed without compromising the seal of the
tank or pipe. The temperature sensor measures temperatures from – 40° to +120°
C and offers, among other features, two programmable switching points, freely
selectable hysteresis and a temperature window function. The device is
available as a 24 V DC device with PNP or analog output as well as a 230 V and
115 V AC model with Opto-MOS. Various cable lengths and optional plug-in or
hardwire connections allow the device to be installed in various
configurations. The thread is a G1/2 gauge.
Installation
EGE
temperature sensors can be installed in standard T-pieces or welded T-pieces.
The packing is made with an additional flat seal or with other suitable
materials. Please note the temperature and pressure resistance of the seals for
increased process conditions. Fixing the sensor in the T-pieces is only allowed
on the screw head of the sensor.
After the
installation the display can be turned through an angle of 330° for best
reading. In applications with temperature over +80 °C the sensor should be
mounted from the side into the pipe.
Application
The
hysteresis function is for controlling a temperature value. A limiting value
can be programmed in this mode. As soon as the measured temperature is higher
than the programmed limiting value, the output signals are switched as
programmed (NC or NO). The hysteresis value is the difference temperature for
the switch-on and switch-off signal of the limiting value. An additional time
delay for the switching signals can be programmed for each switching point.
In the
frame function mode the switching function is set depending of a programmed
temperature range. The temperature range starts with the programmed lower value
and end with programmed upper frame value.
The time
delay for the switching signal can also be used in this switching mode.
The
analog output can be use for transmitting the temperature and getting the
proportional current. For that you assign one temperature for the 4 mA
first-value and one temperature for the 20 mA last-value in the programming
mode. Between the temperature values it is permissible to have a minimal
difference of 16 °C / 29 °F.
Approval for safety applications
Sensors for personal security must have a qualifification approval according to EN 954-1 and must be labeled accordingly. Sensors that are not labeled must not be used for applications of this kind.
