WATTECO BoB Assistant, Reference Manual

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Bob Assistant - Reference Manual
2023-04-04 - Version 1.0 35
3.4. ALARM MESSAGE
3.4.1. Payload structure
Evolutions compared to previous version of the device are in red in the following table
Byte
Definition / codec
attribute
Value
(dec) Real_Value
(dec)
Unit Range Type Description
0 Header / alarm 97 const N/A hex=0x61 => a larm header
1 Anomaly level /
anomalylevel
0~127 Value*100/127 % [0,100] float Anomaly level recorded for the alarm
The codec will calculate the battery level value and return it in the
“ anomalylevel ” attribute
2 Temperature /
temperature
0~127 Value-30 °C [-30,97] integer Temperature measured for the sample, which trigged the alarm
event (default anomaly level for the alarm trigger is 25%, can be
changed through a Downlink command, see corresponding chapter)
The codec will calculate the temperature value and return it in the
“ temperature ” attribute
3 NA NA NA NA Reserved for future use
4 Vibration level
(vl_1) /
vibrationlevel
0~127 Value
g [0,127] float
Vibration level measured for the sample, which trigged the alarm
event
vl=(vl_1*128+vl_2+vl_3/100)/10/121.45
The codec will calculate the maximum vibration level value and
return it in the
“ vibrationlevel ” attribute
5 Vibration level
(vl_2) /
vibrationlevel
0~127 Value
6 Vibration level
(vl_3) /
vibrationlevel
0~127 Value
7 Peak frequency
index /
peakfrequencyindex
0~256 Value+1 [0,256]
integer
float Frequency index value with the highest vibration level recorded
Freq_index=Value+1;
The codec will calculate the Frequency index value and return it in
the
“ peakfrequencyindex ” attribute
If peakfrequencyindex value is <128 then Peak frequency step
=3,125Hz
and the corresponding peak frequency value is
Frequency_value=(Value+1)*FREQ_SAMPLING_ACC_LF/256
If
peakfrequencyindex value is >= 128 then Peak frequency step
=100Hz
and the corresponding peak frequency value is
Frequency_value=((Value & 0x7F)+1)*FREQ_SAMPLING_ACC_HF/256
The Frequency value is not calculated by the codec and must be
calculated by the web application
8~39 FFT signal (needed
to be calculated
with vibration level)
/
fft
0~127 g; Hz
float
float
FFT signal measured for the sample, which trigged the alarm event
Value_g=Value*vl/127; (see bytes 2-3-4 for vl value calculation)
The codec will calculate the g value and return it in the “ fft ” attribute
Frequency_hz=(i+1)*FREQ_SAMPLING_ACC_HF/256 (i is the index of
FFT array, begins from 0, ends by 31)