Model 9900RM Gas Analyzer

The new Model 9900RM is a single or multi-component gas analyzer that can be used alone or as an integrated part of a continuous emissions monitoring (CEM) system.


The new Model 9900RM is a single or multi-component gas analyzer that can be used alone or as an integrated part of a continuous emissions monitoring (CEM) system. The analyzer is 19” rack-mountable and supports Modbus/RS485 and Ethernet connectivity.  This is a rugged, single or multi-gas analyzer, free of interference from water and CO2.

The Model 9900RM can be configured to measure most gas species that absorb in the UV. Species typically measured directly by the Model 9900RM include: SO2, NO, NO2, H2S, COS, CS2, NH3, and BTX. Up to five components can be measured simultaneously making the system very economical for multicomponent analysis needs.

The simple and robust design of the Model 9900RM is complemented by powerful data processing capabilities. The user-friendly keyboard enables programming of such variables as timing and frequency of local zero and span checks. Both analog and digital outputs are available and serial communications via Modbus protocol. An optional paramagnetic oxygen sensor can be included to provide O2 corrected concentrations.


Species Measured Single Species
Minimum Full Scale
Minimum Full Scale
SO2 10 ppm 20 ppm
H2S 50 ppm 100 ppm
NO 50 ppm 200 ppm*
NO2 100 ppm 200 ppm*
NOx n/a 200 ppm*
* Lower ranges available upon request
Maximum full scale on all systems 100%
Methodology Multiple wavelength, high resolution, non-dispersive ultraviolet
Optional O2 Integral paramagnetic sensor
Accuracy Better than 1.0% of standard full scale range O2 : ±0.1%
Repeatability ±0.5% full-scale of standard ranges O2 : ±0.2% (reading varies by 0.05% due to A/D resolution)
Linearity SO2: < ±1.0% full scale
NO, NO2, NOx, H2S: < ±1.5% full scale
O2: ±0.1%
Response Time 90% in 30 seconds or less
Number of Gases 1 (single species version)
Up to 5 (multi-species version)
Typical Sample Flow 0.25 – 5 l/min (0.6 – 10.5 SCFH)
Sample Gas Requirements Noncorrosive, non-condensing, free from oil and with less than three micron particulates (0-95%, non-condensing)
Sample System Limits 5 psig max (without the dynamic pressure compensation option, the reported concentrations will be directly proportional to barometric pressure)
Pressure and Temperature Compensation Optional
Ambient Conditions
Storage -20 to 60˚C (-4 to 140˚F)
Operating -20 to 50˚C (-4 to 122˚F) without Paramagnetic O2 sensor, 0 to 50˚C (32 to 122˚F) with Paramagnetic O2 sensor 0.95 Relative Humidity
Zero Drift Typically better than 2% full scale standard ranges in 24 hours
Utility Requirements
Electrical 120 VAC +/-10%,  50/60 Hz
240 VAC +/-10 %, 50/60 Hz
Power Consumption < 200 W maximum start-up (from a cold start) with average power dependant on ambient temperature
Outputs Four isolated Analog Outputs, each configurable to 0-20 mA, 4-20 mA, 0-5V DC, 1-5V DC
One configurable relay contact, Form A (SPST), normally open. Switching: maximum 240 V DC, 0.5 A DC, limited to 10 W. Carry: maximum 1.2 A DC
Inputs Two isolated dry inputs
Communications Modbus RTU RS485 and Modbus TCP
Fast Ethernet – network connection
Physical Dimensions (W x H x D) 48.2 cm x 17.7 cm x 60.256 cm (19 in. x 7 in. x 23.7 in.)
Weight 18.2 kg (40 lb)


Model 9900 Gas Analyzer
Heated Acid Gas (HAG) Sampling Probe