ECM NH3 5250, Инструкция по эксплуатации, Страница: 21 / 62

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another module, this user calibration will go with the sensor and be used with the new
module.
SPAN
To perform a SPAN:
1. A span should be performed after the NH
3
sensor and pressure sensor (if so equipped)
have been on for at least 20 minutes.
2. Put the NH
3
sensor and the pressure sensor (if so equipped) in the model gas
calibration apparatus shown in Figure 6 or in the exhaust of an engine.
3. For the case of the model gas calibration apparatus, adjust the flowrates to get
approximately 15% O
2
, 1.5% H
2
O, your target calibration NH
3
ppm (typically 100),
balance N
2
. For the NH
3
tank concentration shown and a target of 100 ppm NH
3
, the
flowrate through flowmeter #2 will be about 1/9
th
that through the bubbler. This will
give the approximate 1.5% H
2
O required. To set the %O
2
and NH
3
ppm level, use a
NOxCANt or NOx 5210T analyzer. With the Type T NOx sensor used in these
devices, NH
3
will be read as NOx. The NH
3
must not be bubbled nor should there be
any condensed water from the output of the bubbler to downstream of the NH
3
sensor.
Otherwise, the condensed water will absorb the NH
3
and the span process will be
problematic.
4. For the case of using the exhaust of an engine to span the NH
3
sensor, you must know
the wet NH
3
concentration from another instrument.
5.
Press the SYS key until “MOd” appears.
6. Press the

key until “CAL” is on the display of the channel to be calibrated. Then
press the ENT key.
7. Press the

key until “NH3” appears. Then press the ENT key.
8. Press the

key until “SPAN” appears. Then press the ENT key.
9. Using the

and

keys, change the display to read the actual NH
3
ppm.
10. Press SYS to return to RUN mode.
11. The user calibration is written into the memory chip in the NH
3
sensor’s connector
and will be used to calculate NH
3
. If the NH
3
sensor is removed and installed on
another module, this user calibration will go with the sensor and be used with the new
module.
FACT (return to factory NH
3
calibration)
To return to the factory calibration for the NH
3
sensor:
1. Make sure the NH
3
sensor is attached to the module.
2. Press the SYS key until “MOd” appears.
3. Press the

key until “CAL” is on the display of the channel to be calibrated.
Then press the ENT key.
4. Press the

key until “NH3” appears. Then press the ENT key.
5. Press the

key until “FACT” is on the display. Press the ENT key. The user
NH
3
ZERO and SPAN calibration of the NH
3
sensor is erased and the factory
calibration will be used to calculate NH
3
.