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Operation Manual HORIBA APDA-371
Particulate Monitor
Date:
April, 2010
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HORIBA Europe GmbH, Julius-Kronenberg-Str. 9, D-42799 Leichlingen, Telefon: +49(0)2175-8978-0, Fax: +49(0)2175-8978-50
Page 43
effect gets worse as the RH increases. The Smart Heater minimizes this effect by actively heating the inlet tube to lower
the humidity.
Heater Setup
RH Control: YES
RH Setpoint: 35%
Datalog RH: YES (Chan 4)
Delta-T Control: NO
Delta-T Setpoint: 99 C
Datalog Delta-T: NO (Chan 5)
SAVE
EXIT
The HEATER Setup Screen
RH Control:
If YES is selected, the Smart Heater will be automatically turned on full power whenever the
humidity of the sample stream exceeds the RH Setpoint. When the RH falls back below the set
point, the heater turns down to a low power heat mode (about 30 Watts) which simulates the older
style wrap-around heaters. If this is set to NO, The Smart Heater will stay in low power mode and no
further RH control will be performed.
RH Setpoint:
The RH Setpoint can be a number from 10% to 99%. This is the relative humidity level that will be
maintained at the filter. HORIBA recommends setting this value at 35%, which is the equilibration
value for FRM filters and is required when monitoring PM
2.5
.
Datalog RH:
If YES is selected, the filter RH values will be logged on channel 4 of the APDA-371. Select YES if
you do not have any external sensors attached to channel 4.
Delta-T Control: The APDA-371 can compare the filter temperature to ambient and calculate the difference (Delta-
Temperature), if a BX-592 ambient temp sensor is attached to channel 6. If YES is selected, the
Smart Heater will be turned down to low power mode whenever the Delta-T Setpoint is exceeded.
Volatile organic compounds (VOCs) may be lost if the Delta-T is excessive. However, this is usually
not a problem with the APDA-371, because each spot of particulate is sampled for less than an hour
before being replaced with a new spot. HORIBA does not recommend using Delta-T control except
in special applications, as it overrides the RH control which has a far greater effect on the
concentration measurement. Note: Delta-T control must be set to NO for PM
2.5
FEM monitoring.
Delta-T Setpoint: This can be set from 1 to 99 degrees C. If the filter temperature exceeds the ambient temperature by
more than this amount, the Smart Heater will turn down to low power mode, regardless of the RH
level. An N error is logged in the data any time this happens. Note: There is often a few degrees of
Delta-T measured even if the heater is OFF, due to mild heating effect of the unit itself. Frequent
errors will be logged if the setpoint is too low. Set this value to at least 8 or 10 degrees C if used. Set
the value to 99 if not used.
Datalog Delta-T: If YES is selected, the Delta-T values will be logged on channel 5 of the APDA-371. Select YES if
you do not have any external sensors attached to channel 5. Note: The measured Delta-T may still
be logged even if Delta-T control is set to NO. This is often a useful parameter.