Operator Manual, Dual-Column Cloud Condensation Nuclei Counter (CCN-200)
DOC-0128 Rev F
7 3
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
12.2.5.1
CCN Alerts and Alarms
Laser Current Status
alerts if the laser draws too much current, indicating the laser diode is nearing
the end of its useful life. Contact DMT. No alarm. Alert Code = 1.
OPC Communication
alerts if the OPC is not communicating with the computer. No alarm. Alert Code
= 256.
1st Stage Monitor Voltage Status
counts when the 1
st
Stage monitor is > 4.7 V. Alerts after 5 minutes.
No alarm. Alert Code = 2.
Flow Status
counts when total flow deviates >20% from the set flow or when the flow ratio is not
within 5-15. Alerts after 30 minutes. No alarm. Alert Code = 4.
Temp Control Status
counts when at least one of T1, T2, T3, T Inlet, T Nafion, and T OPC is more than
10 degrees from its set point. Alerts after 10 minutes. Alarms after 20 minutes. Alert Code= 8.
Sample Temp Status
counts when the sample temperature exceeds the 0-50 °C range. Alerts after 1
minute. Alarms after 5 minutes. Alert Code = 16.
OPC Status
counts when the 1
st
Stage Monitor > 4.7 V and CCN counts are less than the configured
threshold. DMT sets this threshold to the factory default of 10 counts/sec, but it can be changed by
the user using the
CCN Calibration Editor.exe
program. No Alert. Alarms after 60 minutes. Alert Code
= 32.
CCN Concentration Status
counts when CCN counts are less than the configured threshold (factory
default 10 counts/sec). Alerts after 20 minutes. Alarms after 120 minutes. Alert Code = 64.
Column Temps Stabilized Status
counts when T1, T2, or T3 is >0.4 degrees from its set point. Alerts
after 20 minutes. No alarm. Alert Code = 128.
Duplicate File Name Status
alerts when a file already exists with the same name as the file that the
CCN program wants to create. A new file will be created, which will have the same name as the
original file but have “duplicate.xxx” appended to it. Check and fix, if necessary, the system clock. No
alarm. Alert Code = 512.
Safe Mode
flashes
when an alarm has been triggered and the unit is in safe mode. The Safe Mode
indicator is only visible when an alarm is triggered.
Reset Status
clears all alerts/alarms and resets their timers to zero. This button will not turn the TEC
relays back on. It does turn the liquid supply pump back on.
12.2.5.2
How to Interpret CCN Alarm Codes in Output Files
When the CCN is running, any alerts and alarms will be displayed individually in the
Status
window
at the top of the main program screen. In the .csv and serial stream output, however, alerts and
alarms are stored as a sum of all the alarm codes generated. For instance, say the CCN is generating
an alarm code of 183. 183 = 128 + 64 + 1, which means that alerts have been generated for
Column
Temp Stabilized
,
CCN Concentration
and
Laser Current Status.
(Because the alarm code for each
individual problem is a unique 2
n
number, the sum of alarm codes will always indicate a unique set
of issues.) A negative alarm code indicates problems severe enough that the instrument has gone
into safe mode.