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WMBus Smart Building MOTION - Guide utilisateur / User guide version V1.0.0
71
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of 82
FR
4.2.6 Periodic data frame
This frame (0x4E) is sent according to the period chosen by the user (period = S321xS320xS301) and contains the periodic presence count and
brightness rate readings.
Each log contains the number of detections made and the brightness rate corresponding to a size of 3 bytes:
-
the first 2 bytes for presence detection: unsigned 16 bits. For example, the value 1251 represents 1,251 detections.
-
the last byte for the brightness rate: 8 bits unsigned in%. For example, the value 50 represents a brightness rate of 50%.
In WMBus, the maximum transportable in a frame is 15 readings (P+L). The device sends readings from the most recent to the oldest.
0
1
2 and 3
4 and 5
6
7 and 8
9
...
234 and
235
236
Code
PAYLOAD
PAYLOAD
0x4C
Cf Status
Global
presence
counter
Presence
counter
at t0
Brightness
rate at t0
Presence
counter at
t-1
Brightness
rate at t-1
...
Presence
counter
at t-78
Brightness
rate at t-78
0x4E
0xA3
0x0210
0x0053
0x50
00
00
00
00
NOTE: if S301> 80, the warning bit will appear in the byte status. In this case the frame will send the most recent readings at the expense of
the oldest ones that will be potentially lost.
For example, the following frame 4EA30210005350 (in hexadecimal) means:
-
Frame code = 0x4E, periodic data frame
-
Status = 0xA3, meaning a frame counter at 5, a low battery alarm and configuration validation.
-
Global presence counter = 0x0210 i.e. 528 presence detections since device start
-
Presence at t0 = 0x00053 i.e. 83 detections made
-
Brightness at t0 = 0x50 is the brightness rate is at 80%
4.2.7 Presence detection alarm frame
This frame (0x4F) is sent when a threshold defined by configuring register 330 for presence detection is exceeded.
0
1
2 and 3
4 and 5
Code
Status
PAYLOAD
0x4F
Status
Global count of detections since
start up
Counter since the last
frame sent
0x4F
0xA3
0x0320
0035
Its size is 6 bytes.
Description of the frame:
Bytes 2 and 3: global presence detection counter Bytes 4 and 5: counter since last frame sent
In the example in grey, this results in:
Bytes 2 and 3 = 0x0320, the global counter has counted 800 detections since the device was started Bytes 4 and 5 = 0x0035, the counter
has counted 53 detections since the last frame was sent.