GANN Hydromette RTU 600 Betriebsanleitung Seite 20

9.2 General Information About Temperature Measurement
A temperature balance must be achieved between the measuring sensor and the object to be measured, for
correct readings to be made. This is easy to achieve when measuring liquids in large quantities or large
objects with a high heat content. One must ensure that the sensor tube and head are not affected by another
temperature such as ambient air temperature.
Therefore, it is recommended that the sensor be totally immersed or a screen be fitted to the tube. This screen
can be made of polyester or of foam rubber about 3 cm dia., and sufficiently long to protect the exposed length
of the tube which will be pushed through the middle. In the case of surface measurements with temperature
probe OT 100, the block of polyester or rubber foam with a length of side of at least 30 mm will be sufficient
to protect against convection heat or cold when taking temperature measurements on walls.
In the case of materials which are poor heat conductors or of low heat content (e.g. rockwool, glasswool, etc.)
it is often not possible to achieve a correct temperature measurement with electrical sensors. To obtain
utilizable results, it may become necessary either to take into account the ambient temperature or to carry out
approximate measurements.
When measuring insulating materials whose surface temperature generally corresponds to the ambient
temperature, the stick-in temperature probe ET 50 should be used. Measurement or response times do how-
ever increase considerably.
9.3 Use of the active electrode RF-T 28
Hold the probe in the air at the measuring location and start the measuring by pressing the measuring key .
The electrode RF-T 28is only suitable for measuring the air temperature (besides of the air humidity) not for
temperature measurements on solid material and liquids.
For particularly precise measurements, in particular at temperatures below +10 °C or above +40 °C or if there
are significant temperature differences between the temperature of the electrode itself or of the measuring
instrument and that of the surrounding atmosphere, the electrode should be exposed to the surrounding
atmosphere of the measuring location for approximately 10 to 15 minutes or until temperature equalization.
The measuring range from -10 to +80 °C only applies to the sensor tip (length of the protective cap) of the
electrode. The electrode tube with electronics and the measuring instrument may be exposed to temperatures
above 50 °C only for a short time. For the instrument and probes if possible do not allow the operating
temperature to fall below 0 °C or rise above +50 °C.
Falsification of the measured values can occur by screening with parts of the body (e.g. the hand) or by blow-
ing or speaking / breathing in the direction of the sensor.
The adjustment time of the air temperature sensor for 90 % of the temperature jump is in the case of moving
air for the probe RF-T 28 approximately 120 sec., for the probes. The air temperature sensor adjusts to the
surrounding atmosphere also if not switched on.
9.3 Use of the Surface Temperature Probe OT 100
The OT 100 is a special probe with low mass for measuring surface temperatures. Coat the sensor head with
heat conducting paste and press it against the object to be measured. The sensor head must lie totally flat
and in good contact. There must be no air (only a thin layer of heat conducting paste) between the sensor
head and the object to be measured.
The response time ranges between 10 and 40 seconds depending on the material to be measured. In order to
achieve good results, sufficient heat content and heat conductivity of the material to be measured is indispensable.
Note
Avoid damage to the spring loaded tip of the probe by exerting excessive pressure or by bending the tip.
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15.11.2006 Hydromette RTU 600 #013629