Motortech EasyNOx, Operating Manual

Page: 42 / 142

42 Rev. 06/2021
5.1 NO
ₓ
Monitoring
In the following sections, the NO
X
monitoring functions of the EasyNO
ₓ
are described. To use the
NO
X
monitoring in the EasyNO
ₓ
, the EasyNO
ₓ
must be connected to a suitable CAN bus/NO
X
sen-
sor module from MOTORTECH.
5.1.1
Measured Value Display and Measured Value Output
The NO
X
monitoring of the EasyNO
ₓ
displays the following measured values for up to two en-
gines:
– The current nitrogen oxide concentration reading from the connected NO
X
sensor in ppm
– The current oxygen concentration reading from the connected NO
X
sensor in vol.%
– In normal operation, the current nitrogen oxide reading converted according to VDMA
6299:2019-09 in mg/Nm
3
(for further details, see section Conversion of Nitrogen Oxide
Readings on page 42)
– The provisional daily average of nitrogen oxide readings in mg/Nm
3
The NO
X
monitoring calculates the nitrogen oxide daily average from valid readings of the NO
X
sensor in normal operation, provided that the dew point of the NO
X
sensor has been reached at
the catalyst outlet for at least 5 minutes.
In conjunction with the optionally available I/O communication module, the current nitrogen
oxide reading converted according to VDMA 6299:2019-09 or the provisional daily average can
additionally be output to a master control via an analog output.
5.1.2 Conversion of Nitrogen Oxide Readings
The readings from the connected NO
X
sensor are converted according to VDMA 6299:2019-09 in
the NO
X
monitor of the EasyNO
ₓ
.
At first, the oxygen content measured in wet exhaust gas is converted to dry exhaust gas:
In the next step, the measured nitrogen oxide value is corrected by sensor- and plant-specific
NO
2
correction factors:
Following that, this NO
2
-corrected nitrogen oxide value measured in wet exhaust gas is convert-
ed to dry exhaust gas:
5 Functions