METIS M311 / M322 / H311 / H322 (17-pin)
Pyrometer Parameters / Settings
20
6
Pyrometer Parameters / Settings
The pyrometer is ex works ready to measure with the factory settings. The connection to a PC is re-
quired for further adaptation to the measuring task and to configure the inputs and outputs, all settings
can be made via the included software
SensorTools
(see
SensorTools Software
).
Further it is possible to communicate via interface commands directly to the pyrometer (see
Inter-
face Commands
). The commands can be used for writing an own control or can be entered via a ter-
minal software.
6.1
Emissivity Slope
Measuring objects that emit the same on the two wavelengths of a 2-color pyrometer are often referred
to as "Gray bodies" (e.g. well oxidized iron or steel surfaces). They can be measured accurately with the
setting 1.00 for the emissivity slope without correction.
Measuring objects whose emissivity is different on the two wavelengths of the pyrometer (e.g. shiny un-
oxidized metal surfaces) need for accurate temperature measurement a correction setting, the so-called
emissivity slope
Ɛ
2
/ Ɛ
1
. The value can be larger or less than 1, depending on whether the emissivity of
channel 1 or 2 is higher (gain from 1.000 to 0.800, attenuation from 1.000 to 1.200).
Regardless of emissivity slope 1 or above or below is
used to measure, the ratio must remain constant in the
required temperature range. In the software
Sensor-
Tools
the 2-color temperature and those of the two
channels can be displayed at the same time. A 2-color
measurement is possible if the curves of the two chan-
nels in the required measuring range run uniformly par-
allel, so the ratio is constant. If the temperature values of
the curves are identical (at the same emissivity setting),
then the emissivity slope is 1. Do they run parallel, so
the correct value for the emissivity ratio must be found,
such by comparative measurement with a thermocouple
and subsequent ratio setting until the temperatures match.
6.2
Emissivity
ε
(when used in single-channel mode)
The pyrometer also can be used in
single-channel mode, the measure-
ment corresponds to that of a conven-
tional radiation pyrometer. In this
measuring mode the input of an emis-
sivity is necessary.
The emissivity indicates the radiation
capacity of an object to be measured
relative to a blackbody source with the
same temperature. To obtain correct
readings, the emissivity must be taken
into account in the measurement and
adapted for the respective measuring
material on the pyrometer. Each mate-
rial has a max. emissivity of 1 which
can be set, an adjustment of up to 1.2
can be used. The emissivity adjust-
ment above 1 allows for temperature
corrections due to higher background
reflection.
In principle applies: to measure metals
in a short-wavelength spectral range
Measuring object
Emissivity
Ɛ
(Epsilon)
M311/H311
0.7-1.1 µm
M322/H322
1.45-1.8 µm
Blackbody
1
1
Aluminum, shiny
n.s.
0.05-0.2
Aluminum, oxidized
n.s.
0.3-0.4
Aluminum, sandblasted, rough
n.s.
0.4-0.5
Aluminum, black anodized
n.s.
0.9
Lead oxidized
n.s.
n.s.
Bronze
0.2-0.4
0.2-0.4
Iron, liquid
0.15-0.3
0.1-0.25
Iron, shiny
0.3-0.4
n.s.
Iron, oxidized
0.7-0.9
0.65-0.85
Graphite
0.8-0.92
0.8-0.9
Gold, shiny
0.02-0.05
0.02-0.05
Inconel, shiny
0.35-0.45
0.4
Inconel, oxidized
0.65-0.75
0.6-0.7
Copper, shiny
0.10
0.05-0.1
Copper, oxidized
0.3-0.7
0.2-0.8
Magnesium, shiny
n.s.
0.15-0.2
