ABB LS4000 Operating Instructions Manual page 11

Analyzer measuring
principle
Explosion-proof
variants of the
junction boxes
(manufacturer's
part numbers)
LS4000, LS4060 DIODE LASER ANALYZERS | OI/LS4000/O2-EN REV. A
The analyzer consists of a transmitter unit and a receiver unit, which are in-
stalled opposite one another on a process line or stack and connected to each
other via a junction box.
The following components are connected to the junction box:
 Transmitter unit and receiver unit
 T/P probe(s) for dynamic temperature and pressure correction (depending
on application)
 Power supply
 Sensors for analog and digital outputs
 Depending on design: External power supply unit (see Analyzer variants on
page 10)
A PC can be temporarily connected to the junction box for service purposes.
The LS4000 uses the optical measurement method of tunable diode laser
absorption spectroscopy (TDLAS), which is based on the fact that gases ab-
sorb light of specific wavelengths.
In this method, a configurable laser diode in the transmitter unit emits a laser
beam, which passes through the process gas and shines onto the photode-
tector in the receiver unit. The molecules of the measuring components locat-
ed in the optical path of the laser beam absorb the laser light, thereby reduc-
ing the light intensity at the receiver.
A sophisticated signal algorithm records the measured reduction in light in-
tensity and uses this value to calculate the gas concentration in accordance
with the Beer-Lambert law. The influence of temperature and pressure varia-
tions is eliminated by a dynamic automatic correction function.
Variant
ATEX, IECEx, KCs without
power supply
ATEX with power supply
IECEx
with power supply
CSA Div. 1 with power supply
ABB P/N Manufacturer's P/N
758368 Bartec 07-5100-2002/3011
758255 Bartec (Ex-e) 07-5180-2002/3011
Cortem (Ex-d) GUB-02
758308 Bartec (Ex-e) 07-5180-2002/3011
Cortem (Ex-d) GUB-02
758219 R. Stahl 8264/6214-3210
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