NH3 5250 Analyzer

(Measures NH3 in diesel exhaust)

MPN: NH35250-XX Category:

ECM’s NH3 5250 is a versatile and rugged NH3 analyzer for the development of diesel and lean-burn engine (i.e.  λ > 1) SCR (selective catalytic reduction) systems.  NH3 is measured using a ceramic sensor that is mounted in the exhaust of the engine.  Ease-of-use, speed, compactness, and robustness are hallmarks of this technology.  No sample lines or pumps are required, simplifying installation and giving fast response.  Distances of up to 100 meters between the sensor and analyzer are possible with no loss in response time or accuracy.  NH3 sensors have their calibration stored in a memory chip in the sensor’s connector.  Calibration can be performed by the user (Zero, Span) and is written into the same memory chip.  This allows sensors to be calibrated in a central location and distributed to users, ensuring consistent results throughout a large test facility.

The NH3 5250 can be used with all fuel types.  All sensor parameters including sensor voltages, cell resistance, and heater voltage are available for display and output.  A second NH3 channel can be added and displayed/output.

The NH3 5250 is remarkably compact and is suited for both dynamometer and in-vehicle applications.  With six analog outputs and CAN communication, the NH3 5250 can be integrated into any data acquisition system.  To simplify in-vehicle use, the NH3 5250 can be turned on and off with a signal from the vehicle’s ignition switch.  This feature along with the analyzer’s CAN communication capability makes it possible to use the NH3 5250 in the loop of a real-time emissions control strategy.

The control of urea injection in SCR systems is difficult.  Not enough urea and NOx emissions rise.  Too much urea and NH3 emissions and urea use rise.  Urea injection control during transient operation is especially difficult and requires fast NH3 instrumentation.  The NH3 5250 makes this difficult measurement with ease and is a necessary tool for the development of modern SCR systems.


Response Time Less than 1 s
Power 11 to 28 VDC, AC/DC (optional)
Sensor Mounting 18mm x 1.5mm thread
Dimensions 105mm x 64mm x 165mm (W x H x D)
6m cable (std), up to 100m (optional)
Operating Temperature Electronics: -40 to +85°C
Sensor: 450°C (maximum gas temperature for use), 700°C (maximum gas temperature without possibility of sensor damage)
Ranges & Accuracies
NH3 0 to 2000 ppm (±5 ppm from 0 to 200 ppm). For λ > 1 only.
CAN Programmable communication protocol
Analog 6 channels, 0 to 5V linearized and programmable for NH3, etc.

Included Analyzer Components

The base kit includes the following:

Filters Sort results


Each channel will add the following parts:

Filters Sort results


Filters Sort results

Calibration Tools

To ensure the accurate operation of the NH3 Analyzer, we divide the analyzer into two parts: the sensor and everything else.

For the sensor, we have the NH3 Sensor Calibration Add-On Option which is added to the NOx Sensor (Type T and F) Calibrator.  The calibrator requires the addition of a tank of calibration gas, a tank pressure regulator, and some plumbing.  The tank, regulator, and plumbing are not supplied by ECM because, due to the weight of the tank, they are best sourced locally.  ECM can recommend gases and suppliers.

For “everything else”, we have the NH3 Sensor Simulator.  The simulator simulates the voltages from perfect NH3 sensor in a perfectly known gaseous environment.  Thus the analyzer, module, cabling, and the user’s data acquisition system should respond accordingly.  If the expected output of the analyzer is not seen, there is a problem with the analyzer, module, cabling, or the data acquisition system.

Filters Sort results




NH3 5250 Manual (Ver. 2015-02-25, 2 MB)
NH3 5250 Brochure (Ver. 2020-04-24, 233 KB)
NH3 Calibration Instructions (Ver. 2022-09-15, 258 KB)
Rackmount Installation Guide (193 KB)
Vboost Power Supply Brochure (162 KB)
Firmware Update Procedure for Display Heads (155 KB)
ECM Configuration Tool (Ver. 4.48.19, 30 MB)