Lufft CHM 8k, Руководство пользователя, Страница: 43 / 72

Operating Manual CHM 8k
R1.7 / 01-2020
Communication via RS485 & Ethernet 43
Variables
Variable Type Dim. Unit Long description Scaling
voltage_det short time V Detector high voltage 0.1
voltage_las short time V Laser bias voltage 0.001
voltage_led short time V Reference LED bias
voltage 0.001
background_det short time mV Detector background signal
fan short time Fan activity (bit 0 set =
window fan on, bit 1 set =
mainboard fan on)
nn1 short time nn1
nn2 short time nn2
Table 15 Variables in the NetCDF file.
8.4.5 Special values of the evaluation parameters
If evaluation parameters determined by evaluating the backscatter signal cannot be determined, various
special values are written to the corresponding NetCDF variable depending on the cause of the non-
determination. This applies to the NetCDF variables cbh, cbe, cdb, cde, mxd, pbl, pbs, bcc, tcc, vor, voe,
sci and state_optics. Table 16 shows the general meaning of the special values. In deviation from this,
there is only the value -2 for the variables sci and state_optics. The slightly different meaning of the
special values for bcc, tcc and pbs is given in Table 21 and Table 22.
In the standard telegrams, the special values are represented by the characters specified in Table 16
Column 2. Which of the respective variants is used depends on the number of digits of the evaluation
parameter in the telegram.
Special
value Telegram Description
-1 NODET, NDET, //,
/ The evaluation parameter was not found in the signal, for
example no cloud base height with clear sky.
-2 -----, ----, --, - There is a hardware error. No data evaluation is performed,
i.e., no evaluation parameters are determined.
-3
NODET, NDET, //,
/ Due to the algorithm, no value could be determined, for
example if not enough raw data is available for a calculation.
Table 16 Special values of the evaluation parameters.
8.5 Status code
There are two different status code variants, each of which reflects the device status as a 32-bit number.
Table 17
lists the meanings of the individual bits of the status codes, which are known from the CHM 15k.
The output of these status code variants occurs in the web interface and in the NetCDF data. For the
output of these data telegrams, for example in the standard telegram, characters
83 … 90 or in the
extended data telegram with the characters
91 … 98 (refer to Table 8 and Table 9), optionally the
escalated status code is available, refer to section 8.5.1.
The status codes will be illustrated as an eight-digit hexadecimal number. Non-set bits mean that the
corresponding part is running properly. Set bits indicate errors / warnings / information, e.g. shortly after
switching on.