JLG 450A_AJ Series II Service Manual - Manual (Page 153)

SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-113
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 trig-
gered. Variables included in the FSS are defined in the Snap-
shot 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-sec-
onds 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 Informa-
tion 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 referenced during fault diagnosis.
Base definitions are not fault dependent. Additional variables
may be selected for capture 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 defi-
nitions is shown in Figure 3-74.
Figure 3-73. Faults Page with Historic Fault Message