Oshkosh JLG 400S, Service And Maintenance Manual, Page: 201 / 462

SECTION 3 - CHASSIS & TURNTABLE
3120895 – JLG Lift – 3-149
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 at the instance
the fault triggered. Variables included in the FSS are
defined in the Snapshot Base and Snapshot Custom Defi-
nition fields found on the Faults Page. A FSS is saved with
each of the first eight (8) faults for 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.
The memory location of the FDR is 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, the FDR data will not be available. The memory
location of the FSS data is 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 the 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. The 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 the desired vari-
ables from a list. An example of custom fault variable defi-
nitions is shown in Figure 3-88.
Figure 3-87. Faults Page with Historic Fault Message