JLG 450A_AJ Series II Service Manual - Manual (Page 208)

SECTION 3 - CHASSIS & TURNTABLE
3-158 – JLG Lift – 3121180
Once an active fault has occurred, two sets of data are
recorded; fault snapshot and flight data recorder. The fault
snapshot (FSS) is a sample of data taken when the fault
triggered. Variables included in the FSS are defined in the
Snapshot Base and Snapshot Custom Definition fields
found on the Faults Page. An FSS is saved with each of
the first eight (8) faults the first time the fault becomes
active.
Conversely, the flight data recorder (FDR) is a ten-second
stream of data that includes eight-seconds prior and two-
seconds after triggering the fault. An FDR is saved for
each of the first two (2) faults for the first time the fault
becomes active. Variables included in the FDR are defined
in the Flight Data Base and Flight Data Custom Definition
fields found on the Faults Page.
FDR information is stored in RAM, therefore this data is
only available if the ECM has not lost battery power. In
addition, if there is a “Dirty Flash Page” in the ECM, FDR
data will not be available. FSS data is stored in EEPROM
and is retained when the ECM loses battery power.
Both sets of data are accessed from the Historic Fault
Information interface and can be saved to a PC upon
retrieval. Base variables for FSS and FDR are generally
defined by the OEM to include variables most often refer-
enced during fault diagnosis. Base definitions are not fault
dependent. Additional variables may be selected for cap-
ture during a fault occurrence through a single, left-click of
the custom table and selecting desired variables from a
list. An example of custom fault variable definitions is
shown in Figure 3-99.
Figure 3-98. Faults Page with Historic Fault Message