Operator Manual, Dual-Column Cloud Condensation Nuclei Counter (CCN-200)
DOC-0128 Rev F
1 0 3
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
Supersaturation:
The state at which air contains more water vapor than thermodynamically allowed.
The CCN-200 counter uses supersaturation to grow aerosol particles to detectible size.
T Inlet (C):
The temperature of the CCN-200’s inlet manifold. When
T Inlet (C)
differs substantially
from its set point for a sustained period, the CCN-200 computer generates an
Alarm Code
.
T Nafion (C):
The observed temperature at the Nafion humidifier. When
T Nafion (C)
differs
substantially from its set point for a sustained period, the CCN-200 computer generates an
Alarm
Code
.
T OPC (C):
The observed temperature of the CCN-200’s optical particle counter. When
OPC Temp (C)
differs substantially from its set point for a sustained period, the CCN-200 computer generates an
Alarm Code
. Each column has its own
T OPC (C)
reading.
T1 Read (C):
The temperature in the CCN’s top control zone.
T2 Read (C):
The temperature in the CCN’s middle control zone.
T3 Read (C):
The temperature in the CCN’s bottom control zone.
On the CCN-200, these temperatures are measured for each column.
T1 Set (C):
The set point temperature in the CCN’s top control zone.
T2 Set (C):
The set point temperature in the CCN’s middle control zone.
T3 Set (C):
The set point temperature in the CCN’s bottom control zone.
On the CCN-200, these temperatures are measured for each column.
T Sample (C):
output channel that
indicates the temperature of the sample air. When
T Sample (C)
exceeds range for a sustained period, the CCN-200 computer generates an
Alarm Code
. Note that
T
Sample B
is a duplicate of
T Sample A
; the unit only records one temperature for the sample air.
TEC Relay:
A control button on the
Temps
tab that
switches the instrument’s 28 VDC power buss on
and off.
Temp Gradient/Temperature Gradient/Thermal Gradient:
A CCN-200 channel that stores the
temperature gradient along the CCN-200’s wetted walls, i.e.
T3 Read (C)
–
T1 Read (C)
. The gradient
is the controlling factor that determines the instrument’s supersaturation. Each column has its own
Temp Gradient
reading. See
Delta T (C)
for details.
Temps Stabilized:
A Boolean output channel indicating when
T1
,
T2
, or
T3 Reads
differs by > 0.4 °C
from its set point. A value of 1 indicates all three channels are close to their set points. If
Temps
Stabilized
is 0 for a sustained period, the CCN-200 computer generates an
Alarm Code
. Note that
Temp Stabilized
indicates temperature stability but does not necessarily indicate data stability, which
also depends on other factors.
Time:
The time at which the computer writes the data from any given sampling instance to the
output file.
Total Flow (Vccm):
The sum of the
Sample Flow
and the
Sheath Flow.
When the
Total Flow
deviates
from set point for a prolonged period, the CCN-200 computer generates an
Alarm Code.
Valve Set:
The voltage setting for the proportional valve. This setting can be either computer-
generated or manually defined by the user.
Vccm:
Volume cubic centimeters / minute. Vccm is a unit of flow.
