Operating instructions CellaTemp PKx 6x
14
5.14 Lower threshold delay
The output impulse can be lengthened to make sure the output impulse is correctly
identified, e�g� by a downstream control system�
Lower threshold delay: [
d2
] → [
d2.dr
] = 0���10�0 sec�
5.15 Setting the emissivity ratio (two-colour mode)
The difference between measured temperature and true temperature can be
compensated by changing the emissivity ratio� Make this adjustment for selective
interferences or when the emissivity for wavelength 1 and wavelength 2 will be
different because of the material that is being measured�
• Emissivity ratio [
q
] → [
q.ESP
] = 80 - 120 %
The pyrometer has a quick adjustment feature to set the emissivity
ratio� In process value mode, the value can be set directly with the keys
▲or ▼. It is not necessary to access the menu. When simultaneously
pressing the MODE key, the display shows the current measuring tem-
perature while the emissivity coefficient continues to be adjusted in the
background� This is an easy way to determine the emissivity when the
object temperature is known� The changed values are directly adopted�
5.16 Emissivity of materials (one-colour mode)
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 41�
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 tempera-
ture� With the configured lower emissivity coefficient, the pyrometer automatically
compensates for the lower radiation�
• Emissivity: [
S
] → [
S.EPS
] = 10���110%