Siemens 7MC3040-... - Page 27

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Operating manual PA
19
Ambient Temperature Compensation
Under normal conditions, PA pyrometer should produce highly accurate
temperature readings once you have set the emissivity and transmit-
tance factors. Certain conditions, however, will require that you make an
additional correction. Object surfaces which have very low emissivity will
reflect thermal radiation from their surroundings. If your target object is in
surroundings which are hotter than the target itself, and the infrared radi-
ation coming from extraneous sources reflects off of the object, the sen-
sor will collect this additional energy. To ensure that the measurement is
not distorted and that temperature readings are completely accurate, you
should activate „Ambient temperature compensation“ (switch on C001
/ BAC.1)
Now enter the temperature value of the ambient source of radiation and
its influence as a percentage. You will have to determine these variables
first.
Target object
T
O
= 900 °C
Emissivity e < 1
Reflection s > 0
Furnace radiation T
Back
= 950 °C
Source of extraneous radiation.
Example: furnace 950 °C