Protective Window - RayTek TX Operating Instructions Manual

6.9 Protective Window

Protective windows can be used to protect the sensor's optic against dust and other contaminations.
For sensors with plastic lenses the use of a protective window combined with the air purge is strongly
recommended.
The following table provides an overview of the available protective windows recommended for a LT,
MT, HT, G5 and P7 model. All protective windows are also available in stainless steel (...S).
Order number Model
XXXTXACTWL LT
XXXTXACTWLF1 LT
XXXTXACTWM MT
XXXTXACTWH HT
XXXTXACTWGP G5, P7
For special requirements, please ask our Sales Department about our range of special protective
windows.
Models delivered with mounted protective windows are preset as follows:
Basic model Basic model has no adjustable parameter for the transmissivity. The influence of
transmissivity is reflected by a resulting emissivity value. E.g. transmissivity of
protective window is 0.88, emissivity of measured object is 0.95, resulting emissivity
value is set with the two rotary switches to 0.84 (0.88 * 0.95 = 0.84)
Smart model Transmissivity for the protective window is set in the software directly. The emissivity
value is not changed.
Determination of transmissivity of an unknown protective window:
If transmissivity of the measuring screen is not indicated on the data sheet, you can also determine the
transmissivity yourself. Please proceed as follows:
1. Measure the temperature of the target object with the sensing head, without using the protective
window. Note correct setting of emissivity. With the basic model, emissivity is set with the two
rotary switches. For the Smart model, the emissivity is entered in the software and the value for
"Transmissivity" is specified as 1.00.
2. Insert the protective window in the sensing head.
3. If you use the basic model of the sensing head, adjust the emissivity until the same temperature
is displayed, as was determined without the protective window.
If the smart model is used, adjust the transmissivity in the software until the same temperature is
displayed, as it was determined without the protective window.
For more information regarding the mounting of a protective window, see section 8.4
Protective Window on page 35.
TX
Designation Material
none
none (stainless steel) Polyethylene foil
4 red dots Sapphire
3 red dots
2 red dots Calcium Fluorid
Table 2: Protective Windows
Rev. O 06/2011
Transmissivity
Amtir 0.65 0.05
0.75 0.05
0.88 0.05
Glass
0.88 0.05
0.93 0.05
Accessories
Use
max. 300°C (572°F)
for food applications,
non-poisonous, non-fragile
max. 1800°C (3272°F)
max. 900°C (1652°F)
max. 600°C (1112°F)
Replacing a
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