UMAX090690. Version: 1.2 Preliminary Documentation
– May Be Subject To Change
16-37
Function Block
Minimum Threshold
Maximum Threshold
Feedback Overcurrent
Fault
N/A
Charge Profile Regulation
Current Setting
VPS Undervoltage Fault
VPS Undervoltage
N/A
VPS Overvoltage Fault
N/A
VPS Overvoltage
Over Temperature Fault
N/A
Temperature Shutdown
Lost Communication
Fault
N/A
Received Message
Timeout (any)
Table 8
– Fault Detection Thresholds
If and only if the
Event Generates a DTC in DM1
parameter is set to true will the other setpoints in
the function block be enabled. They are all related to the data that’s is sent to the J1939 network
as part of the DM1 message, Active Diagnostic Trouble Codes.
A Diagnostic Trouble Code (DTC) is defined by the J1939 standard as a 4-byte value which is a
combination of:
SPN
Suspect Parameter Number
(first 19 bits of the DTC, LSB first)
FMI
Failure Mode Identifier
(next 5 bits of the DTC)
CM
Conversion Method
(1 bit, always set to 0)
OC
Occurrence Count
(7 bits, number of times the fault has happened)
In addition to supporting the DM1 message, the battery charger Controller also supports
DM2
Previously Active Diagnostic Trouble Codes
Sent only on request
DM3
Diagnostic Data Clear/Reset of Previously Active DTCs
Done only on request
DM11
Diagnostic Data Clear/Reset for Active DTCs
Done only on request
So long as even one Diagnostic function block has
Event Generates a DTC in DM1
set to true,
the battery charger Controller will send the DM1 message every one second, regardless of
whether there are any active faults, as recommended by the standard. While there are no active
DTCs, the battery charger
will send the “No Active Faults” message. If a previously active DTC
becomes inactive, a DM1 will be sent immediately to reflect this. As soon as the last active DTC
goes inactive, it will send a DM1 indicating that there are no more active DTCs.
If there is more than on active DTC at any given time, the regular DM1 message will be sent using
a multipacket Broadcast Announce Message (BAM). If the controller receives a request for a DM1
while this is true, it will send the multipacket message to the Requester Address using the
Transport Protocol (TP).
At power up, the DM1 message will not be broadcast until after a 5 second delay.
This is done to prevent any power up or initialization conditions from being flagged
as an active error on the network.
The Diagnostic function block has a setpoint
Event Cleared Only by DM11
. By default, this is set
to false, which means that as soon as the condition that caused an error flag to be set goes away,
the DTC is automatically made Previously Active, and is no longer included in the DM1 message.
However, when this setpoint is set to true, even if the flag is cleared, the DTC will not be made
inactive, so it will continue to be sent on the DM1 message. Only when a DM11 has been
