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6.1.3
Basic protocol commands
The following table details the essential commands used to control the WSU. The full protocol includes
many more messages, is capable of controlling multiple WSUs on the same bus, and gives detailed
fault and status information.
Message
Name
ControlModule
Note: ClearFaults will not clear over voltage protection (OVP) and over current protection (OCP).
6.1.4
CAN bus watchdog
If the WSU is under CAN bus control it must receive frequent messages on ID 0x190, otherwise it will
disable its output and indicate "Fault_WD_Comms". This is an important safety feature as when the
WSU is being controlled by CAN bus, it is the responsibility of the system to ensure safe operation of
the WSU. Without this feature, if the system lost control of the WSU perhaps due to a broken cable,
resulting in a potentially hazardous situation.
It is recommended that the 0x190 message be sent to the WSU every 100 ms.
6.2
manufacturers covering a range of battery constructions, e.g., lithium and lead acid (AGM, gel, TPPL).
logic levels to start and stop the charging process.
A high voltage level presented between pin 1 ("EXT_Enable") and pin 3 ("EXT_Signal_GND") of the
(range 2.7 V to 5.5 V), and a low voltage level should be less than 0.3 V or NC (not connected). The
26
Message
Signal name
ID
0x190
Demand_V
Demand_
PowerStage1
Demand_
ClearFaults
Demand_I
► Caution:
further advice.
Start
Length
Factor
bit
0
20
0.001
20
1
1
21
1
1
32
18
0.001
Unit
Description
V
The target voltage the WCS
is to achieve by providing
current to the battery. When
the battery terminal voltage
reaches this value, the
charging current will reduce
(eventually to 0), to maintain
the voltage.
1 = Turn on
1 = Clear Faults
If the fault condition no
longer exists, charging will
resume
A
The maximum current used
to reach or maintain the
target voltage.
, a low
V
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