DURAG D-LX 200, Manual

Page: 109 / 116

Glossary
D − LX 200, D − LX 720
109
13 Glossary
Background radiation influence
Radiation from static emitters, like
incandescent boiler components, can be
modulated by combustion air currents or
flue gas plumes. If the measured radiation
is in the range of the flame spectrum and in
the normal flicker frequency range (approx.
10 to 200 Hz) of a flame, monitoring
systems can mistakenly detect a flame
signal. Modern flame monitor systems must
be able to filter out this "background
radiation influence".
Claus plant (SRU, sulphur recovery unit)
All H
2
S-containing exhaust gases that
develop are processed in the Claus plant.
The toxic H
2
S is converted into elementary
sulphur and water during this process.
CPU
The main processor (
Central Processing
Unit
; abbreviated to
CPU
]), often also
simply referred to as the processor in
general usage, is the central processor of a
computer, which controls all other
components.
Cyclical communication Interface
communication in which data are bundled
into data packets and transferred in a
defined order, separated by defined
characters (e.g. semicolon).
Data bus
The bus is a frequently used term in data
processing for a wiring system for data
exchange between potentially more than
two nodes.
A bus is a wiring system with associated
control components, which serves for the
exchange of data and/or energy between
hardware components. Bus systems are
particularly used inside computers and to
connect computers to peripheral devices,
but also in the control of machines.
A field bus is an industrial communication
system, which connects a multitude of field
devices such as probes (sensors), actuating
elements and drives (actuators) to a control
device. Field bus technology was developed
in the 80s, in order to replace the previously
standard parallel wiring of binary signals
and analogue signal transmission with
digital transmission technology.
DIP switches
are small switches which are used (e.g. on
the motherboard or other printed circuit
boards) to perform defined basic settings.
The abbreviation stands for dual in-line
package, i.e. a configuration with two
parallel series of connections.
Flame intensity
The flame intensity results from the
(

) flame signal and offset against the gain
settings. It is digitally calculated as a
numerical value (from 0 to 2²³) and output
as 0…100%.
Flame signal
An (analogue) current is generated by the
flame in the photodiode and subsequently
further processed in the analogue amplifier
and analogue filters. This flame signal
(AC/DC) is sent to the microcontroller inputs
for further digital processing.
Flame radiation
is the visible and non-visible (IR/UV) light
emitted by the flame.
Harmonic detection
The flicker frequency of a true combustion
process fluctuates.
A flicker frequency that remains constant
over several seconds can therefore not
originate from a flame. This situation is
identified and results in an error message
after 10 seconds. Also see chapter 9.5.3 on
page 98.
Low-NOx
In this incineration technique, the flame
temperature is reduced by recirculating
exhaust gases from the combustion
chamber, so that the flame is cooled. This
results in a considerable reduction in
pollutants, particularly nitrogen oxides.
Modbus (interface communication)
The Modbus protocol is a communication
protocol based on a master/slave or
client/server architecture. Modbus has
become a de facto standard in industry, as
it is an open protocol.
A master (e.g. a PC) and several slaves
(e.g. measurement and control systems)
can be connected by means of Modbus.
NPT
The National Pipe Thread (NPT thread,
NPT pipe thread) in accordance with
ASME/ANSI B1.20.1 is a US thread
standard for self-sealing screw pipe
connections.
The seal is obtained as a result of the