4.3811.00.000_US-Anemometer-DSP_eng.doc
17 - 26
021511/10/06
7.5.3 Definition of temperature difference in status byte
Bit 2 Bit 1
Temperature difference x to y path in Kelvin
0 0
0.0 K
to
3.1 K
0 1
3.2 K
to
6.3 K
1 0
6.4 K
to
7.9 K
1 1
≥
8.0 K
→
invalid measurement
7.5.4 Definition of averaging memory used
Bit 4 Bit 3 Averaging memory used
0
0
Averaging memory content level > 80%
0
1
Averaging memory content level > 66%
1
0
Averaging memory content level > 33%
1 1 Averaging
memory
empty
7.6
Behaviour in fault conditions
The ULTRASONIC is equipped with a highly effective internal fault detection and correction system.
This allows it to detect incorrect measured values using the history and to discard them.
It cannot however be ruled out that the ULTRASONIC will get into a situation in which the
acquisition of new data is impossible. In this case the error bits are set in the status values and a
defined value possibly output at the analog outputs.
It is a basic rule that the measured values output are always valid and can be interpreted by the
target system (unless a specific error telegram is output in the case of error). However, what may
happen in the case of error is that the data become 'too old', i.e. are not updated over a certain time
and freeze. In this case the error bits are set in the status byte. If a special error telegram is defined
with a serial telegram, this is output.
This device version outputs an error in the status byte if no new data can be determined for
approx.10 seconds.
7.7 Heating
control
To prevent the device from freezing the ULTRASONIC is equipped with built-in heating for the
sensor arms. In standard mode the heating is controlled by the system status. If control of the
heating is software-set, the heating system will switch on under the following conditions:
Acoustic virtual temperature < 2°C
Continuous measuring error > 3sec
