Trace humidity measurement, ATEX certified

SS2100 H20

rapid speed of response
low cost of ownership
high accuracy

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Using a laser to monitor low level humidity offers a number of key benefits.

This robust, non-contact analyser is highly accurate with an extremely rapid speed of response, and has led the industry to a new era in dew point and water vapour measurement. The ability to monitor humidity in near real time has led to significantly improved confidence in the measurement, and improved process efficiencies. The speed of response of the analyser enables rapid detection and recovery from process upsets, allowing easier diagnosis of plant problems and rapid return to normal process level, allowing quick return to shipping product.

The graph below shows the difference in response between a laser system and a more traditional aluminium oxide sensor to short bursts of water vapour. The laser shows a full scale deflection, while the aluminium oxide shows hardly any change.

speed of response graph

See the video on the More Data Tab.

  • Non-contact with the process gas: the active measurement system is mounted behind a window, making this technique a robust measurement system with corrosive and contaminated gas streams.
  • Rapid response: near real time process control can be achieved, improving process efficiency, and, in some cases, allowing the cost of process plant to be reduced.
  • Low maintenance: with no consumables or moving parts, this analyser has very low operational costs and can provide a short return on investment.



Water vapour

Measurement principle

Absorption spectroscopy using a tunable diode laser


0 to 50/100/200/500 or 1000 ppmv


Other ranges available on request

Analogue output

4 to 20 mA configurable


+/- 4 ppm, range dependent *

Response time

Typically less than 20 seconds*

Operational temp. range

 -20 to +50 °C

LCD Display

Concentration, cell pressure & temp. & diagnostics



ATEX systems are CE compliant


Ex II 2G, Ex d IIB+H2 T4,

II2D ExtD A21 IP66 T135°C


Shipping weight

Approx 86 Kg



670 H x 470 W x 377 D mm

Material (wetted parts)

316 stainless steel standard *


Aluminium epoxy coated

Pressure to cell

70 kPaG (10 PSIG)

Pressure to sample cabinet 

Between 140 to 350 kPaG (920 to 50 PSIG)

Sample flow rate

0.1 to 4 S l/min.*

Ingress protection





100 to 240 VAC, 50 to 60 Hz, 300 W



Qty 2, isolated 4 to 20 mA, 1200 Ω at 24VDC

Relay contacts

Qty 1 general fault, Qty 1 Hi/Lo alarm

Digital 1

RS-485 half duplex & 10/100 ethernet (Standard)

Digital 2

RS-232 (Optional)


Modbus Gould RTU or Danial RTU or ASCII

* Application dependent

All specifications subject to change

Sample systems

IMA build bespoke integrated sample systems to provide full measurement systems.

Contact us to discuss your requirements for:

  • sample probes
  • fast loops
  • heated tube bundles
  • pressure reduction & pressure relief
  • filtration