LumaSense Technologies IS 5/F - Handbuch (Seite 23)

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23
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Flame temperature and optical thickness
Into the calculation of the flame temperature both the soot factor and
transmission of a view glass may be considered. For this the emissivity
must be set to the value of view glass transmission.
The device calculates the optical thickness of the. It is influenced by the
soot content and the flame thickness. From the optical thickness (oD) the
absorption (
α
) of the flame can be determinated by using the
equation:
α = − −
1 e
oD
.
Quotient temperature
Via interface may be read the internal calculated quotient temperature.
The calculation includes ratio correction but an entered response time and
the peak memory have no effect.
One-channel temperature (Intensity pyrometer mode)
Via interface may be read the internal calculated one-channel temperature.
The calculation includes emissivity but an entered response time and the
peak memory have no effect. The one-channel temperature is helpful to
calculate the product of emissivity, surface coverage and transmission of
the measuring distance (
τ
-factor). If this falls below the minimum intensity
(the limit is adjustable via interface) the quotient and the flame
temperature are set to lower limit of measuring range. To simplify the
device adjustment the one-channel temperature may be send to the analog
output. (ref. Laser)
Internal temperature
The internal temperature is readable via interface and is generally about
2...3 °C higher than the device case temperature. If it reach 50 °C, the
laserpointer gets disabled. At 70 °C (if 4...20 mA is selected) the device
sets the output to 0 mA („breakage in the thermocouple“). Internal
temperatures above 50 °C are registrated in an internal nonvolatile
memory and can be read out via interface.
Address
If more than one device operates on a bus (RS485), each device needs its
own address. Valid addresses are 00 to 97 (ex works setting is 00);
independently of its own address each device may be addressed with the
global address 99. In this way it is possible to read out the parameters of a
device with unknown address. Using address 98 (‘broadcast’) it is possible
to send commands to all members of the bus; no device will send an
answer.
The device address may only be changed via interface.