Keller 1110968, Руководство по эксплуатации, Страница: 9 / 30

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Operating instructions CellaTemp PR xx
5.6 Internal signal processing
Temperature
↓
Switch point → no / nc → Lower- / upper threshold delay
↓
Switching
5.7 Analogue output
The pyrometer is equipped with an analogue output OUT2 0/4���20 mA� The
maximum load is 500 Ω. The output current is linear to the measured temperature.
Within the overall measuring range, the required measuring range can be set to °C
or °F using parameter [ASP2] (scale beginning) and parameter [AEP2] (scale end)�
There is also the possibility, to switch OUT2 between 0 - 20 mA and 4 - 20 mA�
Scale beginning [ASP2]
Scale end [AEP2]
Change 0/4 - 20 mA [Ao2] =
0: 0 … 20 mA
1: 4 … 20 mA
Parameter Ldx. Subindex /
bitOffset
Value range Slope
Ao2 629 0 0: 0 … 20 mA
1: 4 … 20 mA
ASP2 630 0 Start of measuring range * 10 0�1
AEP2 631 0 End of measuring range * 10 0�1
5.8 Emissivity of materials
The pyrometer reacts to the thermal energy (infrared radiation) emitted by an
object� The ability to radiate heat depends on the type of material and its surface
properties� A description of the calculation of emissivity is in Chapter 16/ Page 30�
The ability of a body to emit infrared radiation is expressed by a material constant
called emissivity coefficient or just emissivity� This coefficient lies between 0 and
100 %� A body with ideal radiation (black body) has a coefficient of 100 %� At the
same temperature, bodies with real radiation emit a lower radiation� Therefore, the
emissivity coefficient is < 100%� For this reason, adjust the emissivity coefficient of
the target object on the pyrometer to be able to determine the exact temperature�