Operating Manual CHM 15k
R13 / 07-2019
Communication via RS485 & Ethernet
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dt(s):
Logging time interval (in automatic mode identical to the reporting time). A longer time interval
leads to time averaging over more photon pulses (shots) and thus to an improved signal / noise ratio. An
increase by the factor n leads to an improvement by the factor root n. All raw data in the time interval
dt(s) are included in the evaluation. Single data selection does not take place.
DeviceName
(old FabName)
:
Device acronym (CHM) combined with the serial number of the device,
e. g. CHM060001.
IgnoreChars:
Specific 2-character HEX codes, e. g.
“06” corresponds to <ack>, can be added to a list
of characters that should not be evaluated by the CHM 15k instrument.
Institution:
Institution or company.
Lasermode:
Switches the laser on / off, useful option for testing.
LaserPower:
Laser power in mW.
Latitude:
Latitude of the location, decimal, example Berlin: 52.51833 (corresponds to 52° 31' 6'' N).
Layer (Number of Layers):
Number of cloud layers displayed in the extended telegram and NetCDF file.
Lifetime(h):
Queries the operating hours of the laser (laser lifetime).
Location:
Sets / queries the location of the device. The name of the device is limited (max. 31 characters,
\ / : * ? " < > | _ # % are not allowed).
Longitude:
Longitude of the location, decimal, orientation to east positive, example Berlin: 13.40833
(corresponds to 13° 24' 30'' E).
MaxCrossTalkChars:
The number of characters the CHM 15k will ignore within the time interval
“TimeOutRS485(s)” if not ended with <EOT> (04 HEX), <CR> (0D HEX), <LF> (0A HEX).
The parameter is included to prevent the ceilometer to fall back in its standard baud rate caused by noise
on unstable communication lines.
Parameters:
Queries the complete parameter list for RS485.
RS485Number:
Designates the identification number in a RS485 bus system that is required to select a
specific device via a data interface. In addition to the specific address, each CHM device responds to the
universal identification number 99.
Standby:
Switches off laser, heater and fan.
SystemStatusMode:
Defines the status code variant to be used in the data telegrams. 0 = previous
status codes used by CHM 15k before firmware 1.x, 1 = escalating status codes, see 8.5 Status code.
TimeOutRS485(s):
Sets a time interval for MaxCrossTalkChars and BaudAfterError (default 30 s).
Time Zone offset hours:
Must be set to correct for local nighttime, e.g. to switch off the fans at night.
The system itself operates in UTC time.
TransferMode:
See 8.3.1 Polling mode to 8.3.5 Raw data telegram.
Unit(m/ft):
Specifies the target units in meters (m) or feet (ft).
UseAltitude:
Inclusion of Altitude(m) in the data output. For example, an entry of 60 m for the altitude
increases the transmitted cloud base height by 60 m if UseAltitude is set to 1 (true).
Zenith:
Specifies the vertical angle in degrees, the Sky Condition Algorithm (SCA) uses this angle to
calculate the actual height of the cloud base.
Summary of Contents for CHM 15k
Page 1: ...General Information 1 Titelseite...
Page 73: ...Index of Tables 73...
