The Series IV QUASAR Chemiluminescence detector (CLD) NOx gas analysers combine high levels of performance with flexibility and ease-of-use in the continuous measurement of NOx, Nitric Oxide, Nitrogen Dioxide or Ammonia.

Reference Method
Heated vacuum chemiluminescence is the reference method for monitoring NOx (combined NO and NO2), offering  higher sensitivity with minimal quenching effects, and a heated reaction chamber facilitates the processing of hot, wet sample gases without condensation. The reaction of NO (Nitric Oxide) and O3 (ozone) to produce the chemiluminescence is greatly improved under vacuum, with a better signal to noise ratio, and a fast response time makes it ideal for real-time reporting applications. This method is specified in many standards, such as EN 14792 and Method 7E.

NEW - Removable Screen option
Every Series IV analyser can now be supplied with a rugged, detachable screen which connects wirelessly to the analyser via an inbuilt 802.11 wifi that can connect up to 50 metres away. This provides users with the ability to view live data in a different location, and even manage data logging, alarms and calibration.

Signal CLD analysers – better by design
Heated sample lines and the analyser vacuum prevent water condensation (without any need to remove it) so that NO2 (Nitrogen Dioxide) cannot dissolve in water. The QUASAR also features a unique neon tube ozonator, which means that (free) air can be used as a feed gas.
Signal also provides a non-vacuum and moderately heated Chemiluminescence analyser for applications where trace NOx needs to be measured, for measuring dilute vehicle exhausts from CVS (constant volume sampler) systems and RDE (Real-world Driving Emissions) on-board vehicle testing (for which a 24VDC version is available). Signal also recommends this analyser for CEMS (continuous emissions monitoring) applications, however flue gas should be cleaned and dried before the analyser, to maximise maintenance intervals.

Four versions of the QUASAR:

  • Single detector heated, vacuum type, manual switching for NO, NOx and by subtraction, NO2.
  • Dual detector heated, vacuum type, continuous measurement of NO, NOx and NO2.
  • Single detector, 50 Deg C detector, non-vacuum type.
  • Ammonia measurement version.

Remote connectivity
With 3G, 4G, GPRS, Bluetooth, Wifi and satellite compatibility, Series IV instruments each have their own IP address and run on Windows software. This provides users with simple, secure access to their analyzers at any time, from anywhere, making these instruments ideal for remote sites and for customers with multiple sites. Remote connectivity saves time and money, and creates new possibilities for enhanced reliability. Users (and Signal’s service engineers, on request) can monitor the status of analysers remotely, so that timely service interventions can take place when required rather than on a timed schedule. This reduces potential downtime and lowers the cost of ownership.

OEM Version
An OEM version of the PULSAR is available for systems integrators. This is supplied without the touch-screen front panel and utilises Windows software to run the entire functionality of the analyser from a remote PC.


Download a low-resolution copy of the new Series IV QUASAR brochure 


This e-mail address is being protected from spambots. You need JavaScript enabled to view it. to request a high-resolution print-ready copy


Key Features

 very low quenching from CO2 and H2O

 electronic proportional flow controllers

 special ozone generator uses air as feed gas

 long life NOx converter (5 years)

 dry, low-maintenance pump

 24V DC version (ideal for PEMS applications)



 Environmental compliance

 Combustion analysis

 Process monitoring

 Automotive exhaust emissions (fixed or mobile)

 Gas turbine emissions