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​Model T204
with NumaView™ Software
NO/NO2/NOx/O3 Analyzer​ 



  • Simultaneous NO, NOx, NO2 and Ozone readings
  • Compact, cost-effective analyzer
  • Independent Ranges and Auto-Range
  • Large, vivid color display with touch screen interface
  • Ethernet, RS232 and (optional) USB com ports
  • Adaptive signal filtering optimizes response time
  • Ability to log virtually any combination of operating parameters
  • Optional analog inputs
  • Optional Zero/Span Valves
  • US EPA Federal Equivalent Method EQOA-0514-214 for Ozone
  • US EPA Federal Reference Method FNA-1194-099 for NO2
  • Two-year warranty
  • Technical support for the life of the instrument


​The following table provides a list of items that need regular maintenance to ensure your product remains in good working condition.

TEST functionsReview and evaluateWeeklyNo
Particulate filterChange particle filterWeekly (if in stack system: As Needed)No
Zero/span checkEvaluate offset and slopeWeeklyNo
Zero/span calibrationZero and span calibrationEvery 3 monthsYes
External zero air scrubber optionExchange chemicalEvery 3 monthsNo
External dryer optionReplace chemicalWhen indicator color changesNo
Ozone cleanserChange chemicalAnnuallyYes
Reaction cell window (“optical filter” in Figure 11‑5)CleanAnnually or as necessaryYes
DFU filtersChange particle filterAnnuallyNo
Pneumatic sub-systemCheck for leaks in gas flow pathsAnnually or after repairs involving pneumaticsYes if a leak is repaired
Reaction cell O-rings & sintered filtersReplaceAnnuallyYes 
PMT Sensor Hardware CalibrationLow-level hardware calibrationOn PMT/ preamp changes or if slope is outside of 1.0±0.3Yes
PumpRebuild headwhen RCEL pressure exceeds 10 in-Hg-A (at sea level)Yes
Inline Exhaust ScrubberReplaceAnnuallyNo
NO2 converterReplace converterEvery 3 years or if conversion efficiency drops below 96%Yes 
Desiccant  bagsReplaceAny time PMT housing is opened for maintenancen/a
O3 Sensor Maintenance
Internal Particulate FilterReplaceMonthly*No
UV LampAdjustAs neededNo
UV LampReplaceWhen adjustment no longer effectiveNo
Sensor Module ValveReplace~ Every 2 yearsNo
*or every 6 mo. when external sample line pre-filters are used. 
 ​ ​


07889A - T204 Operation Manual.pdfT204 Manual9308 KB
08296D - Addendum,  NumaView(TM)Software-for-Analyzers.pdfNumaView™ Software Addendum for Analyzers7097 KB
ESD Fundamentals - 04786.pdfFundamentals of Electro-Static Discharge (ESD)216 KB
NVS Remote Manual - 08492.pdfNumaView™ Software Remote User Guide867 KB
SAL000079C - T204.pdfT204 Specification1257 KB
SAL000079C-CN T204.pdfT204规格 (Chinese Specification)3713 KB
T SERIES_6PG.BROCHURE_2018_web.pdfT Series with NumaView™ Software Brochure9567 KB


General Nitrogen Oxides (NOx) Sensor Ozone (O3) Sensor
Ranges Min: 0-50 ppb Full scale
Max: 0-20,000 ppb Full scale (selectable, dual-range supported)
Min: 0-50 ppb Full scale
Max: 0-1,000 ppb Full scale
Measurement Units ppb, ppm, μg/m3, mg/m3 (selectable)
Zero Noise < 0.2 ppb (RMS) < 1 ppb (RMS)
Span Noise < 0.5% of reading (RMS) above 50 ppb or 0.2 ppb, whichever is greater < 0.5% of reading (RMS) above 0.1 ppm
Lower Detectable Limit 0.4 ppb < 2 ppb
Zero Drift < 0.5 ppb/24 hours < 1% full scale/24 hours
Span Drift < 0.5% of full scale/24 hours < ​1% full scale/24 hours
Lag Time < 20 seconds < 10 seconds
Rise/Fall Time < 60 seconds to 95% < 30 seconds to 95%
1% of full scale​
Precision 0.5% of reading above 50 ppb 0.5% of reading above 100 ppb
Sample Flow Rate 500 cc/min ±10% 800 ​cc/min
Power Requirements
100-120V, 60 Hz (3.0 A); 220-240V, 50 Hz (2.5 A); 220-240V, 50/60 Hz (2.5 A)
Analog Output Ranges 10V, 5V, 1V, 0.1V (selectable) All Ranges with 5% under/over range
Recorder Offset ±10%
Standard I/O 1 x Ethernet: 10/100Base-T
2 x RS232 (300-115,200 baud)
2 x USB device ports
8 x opto-isolated digital outputs
6 x opto-isolated digital inputs
4 x analog outputs
Optional I/O 1 x USB com port
1 x RS485
8 x analog inputs (0-10V, 12-bit)
4 x digital alarm outputs
Multidrop RS232
3 x 4-20mA current outputs
Operating Temperature Range 5 - 40ºC (with US EPA Approvals)
Dimensions (HxWxD) 7” x 17” x 23.5” (178 x 432 x 597 mm)
Weight Analyzer: 40 lbs (18 kg)
External pump: 15 lbs (7 kg)
Humidity Range 0-95% RH non-condensing

Specifications are subject to change without notice.
All specifications are based on constant conditions.​
US EPA: EQOA-0514-214 (Ozone)
US EPA: RFNA-1194-099 (NO2) ​​​​​​​


The Model T204 combines proven Chemiluminescence and UV absorption measurement technologies together to create the world’s first US EPA-approved NO / NO2 / NOx / O3 instrument.​ The Model T204 is ideal for urban airshed monitoring, traffic studies, or stand alone NOx/O3 monitoring. ​The T204 allows reduced integration and procurement costs while providing a simple, stable, and reliable monitoring solution.

The chemiluminescence NO/NO2/NOx channel uses the proven TAPI optical bench and pneumatics of the T200, while the compact UV absorption ozone sensor is adapted from the TAPI 465L ambient ozone monitor. In combination, these two technologies solve many of the problems of users that require a high performance analyzer in a smaller, more cost-effective package.

All T Series instruments offer an advanced color display, capacitive touch screen, intuitive user interface, flexible I/0, and built-in data acquisition capability. All instrument set up, control and access to stored data and diagnostic information is available through the front panel, or via RS232, Ethernet, or USB com ports, either locally or by remote connection.

The Model T204 comes with the Numaview™ Software. NumaView™ Remote PC Software allows for a remote connection with virtual interface and data downloading capability to analyzers operating NumaView™ Software.​