10
Operating instructions CellaTemp PK / PKF / PKL xx
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 [
Ao. _
] (scale beginning) and parameter [
Ao. ~
]
(scale end)� There is also the possibility, to switch OUT2 between 0 - 20 mA and
4 - 20 mA�
Scale beginning [
Ao
] → [
Ao. _
]
Scale end [
Ao
] → [
Ao. ~
]
Change 0/4 - 20 mA [
Ao
] → [
Ao.04
] =
0-20
/
4-20
First, the beginning of the scale [
Ao. _
] in °C or F is entered, then the end of
the scale [
Ao. ~
]� By changing [
Ao. _
] also changes [
Ao. ~
], so that the
range remains the same� If [
Ao. _
] is increased so far, that the range can not be
adhered to, as [
Ao. ~
] would otherwise exceed the maximum, [
Ao. ~
] is kept
at its maximum� If [
Ao. _
] is then reduced again, [
Ao. ~
] is also immediately
reduced again� The minimum span is given in the technical data of the respective
device�
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�
With the configured lower emissivity coefficient, the pyrometer automatically
compensates for the lower radiation�
• Emissivity: [
EF
] → [
EPS
] = 10���110%
• For the emissivity, the pyrometer has a quick adjustment function� In the
process value display the value can directly be entered by using the ▲or ▼
button without changing to the menu� When simultaneously pressing the MODE
