NOVA

NOVA uses the very latest tunable laser diode technology to meet the growing requirement for and accurate NO measurement in the tunnel environment.

Unlike previous generations of open path NO monitor, based on broadband IR technology, the highly sensitive laser technology is virtually unaffected by humidity and offers readings accurate enough to make inferred measurements of NO2 and NOX also.

Laser technology offers a future proofing benefit that is invaluable in itself, but the NOVA also has a relatively low cost of ownership and minimal maintenance requirements, making it an attractive proposition for tunnel operators.

NOVA has a stand alone capability, so provided with power (either 24vdc, or 85-265vac) it can be set-up and controlled using a PC (local or remote), and provide a full complement of outputs, including:  4-20mA, relay contacts, standard serial comms (RS232/485), and optional bus interfaces including ModBus, Profibus, DeviceNet, Ethernet etc. Alternatively an optional Operator Interface (OI) is available (with keypad and display) which can provide the same outputs remotely.

The analyser consists of a transmitter head (Tx) and receiver head (Rx) mounted 20m apart on the tunnel wall or ceiling. The Tx emits an infrared (IR) laser beam (eye safe) which makes a single pass across the 20m open path between Tx and Rx. The beam is pulsed at a fixed frequency so that the Rx can differentiate between the laser energy and any stray radiated energy from the ambient tunnel environment. The laser energy is collected at the Rx, where all signals are processed and readings are generated.

The NO measurement is made using a variant of the NDIR absorption technique, but the lasers ability to accurately generate a single wavelength radically improves the performance of this technique. 

Use of the groundbreaking tunable laser diode technique, in opposition the conventional broadband IR technology, has resulted in an analyser that sets new standards for accuracy and stability amongst its rivals, whilst almost completely eradicating the sensitivity to humidity traditionally found in open path NO monitors.