Bob Assistant - Reference Manual
2023-04-04 - Version 1.0
39
4.7.
Change Vibration threshold for On/Off detection
–
New
Sometimes the environment can be very noisy with a lot of parazitic vibrations, due to close proximity
with other highly vibrating equipments. It could happen that BoB analyses these vibrations and consider
them as legitimate as the level will be high enough to consider that the machine is On.
In that case, it is possible to adjust the vibration threshold to consider that the machine is On or Off.
For example, a machine with a vibration level at 0.3g when On could sense 0.05g due to parasitic
vibration when the machine is Off. In that case it will not consider the equipment as off, and report false
inforamtion on the vibration of the equipment.
In that case, it is possible to send a downlink to the device to adjust the threshold to 0.155g for example.
To do so, you need to put the value in dg (multiply by 100 the expected threshold):
New vibration threshold = 0.155g => value to send = 0.155x100 = 15.5 (10
-2
g)
You then need to transform this float value into hex value:
15.5
0x41780000
To prepare the frame to send by downlink, you then need to put the hex value in LSB first format:
0x41 78 00 00
0x00 00 78 41
Then you just need to add the header of the frameto complete the payload to send:
5D00007841
Definition
Downlink value (hex) Downlink Port
Set minimum vibration threshold value
0x5Dtttttttt
1
With
tttttttt
= 10
-2
g value converted in hex format with LSB first, e.g. 00007841 for 0.155g
Note: You can use an online decimal to hex converter to get the hex value from the float value (e.g.
https://www.binaryconvert.com/
