Snapshot -726280184

TM 9-2320-364-20-1

2-11. TROUBLESHOOTING INSTRUCTIONS (CONT).

NOTE

If you change your mind while creating a custom list, you can use the LEFT arrow key

to back up through the list. When the item you wish to change appears, simply scroll

the parameter list to locate the new item and ENTER it. Also note that backing up

through the list erases each item you pass through. You will have to recreate the list

from the point of the change item.

(10) Snapshot. The Snapshot function permits the DDR to record data while the truck is being driven. Then

the data can be played back when you return to the shop. You can use this feature to locate operating

problems that would be difficult to locate by any other method. Depending on truck type and the data

rate, the DDR will record over 50 minutes of data.

NOTE

The amount of information that can be recorded is determined by the data update rate

selected. Refer to Step (11)(f) (Data update rate).

(a)

When you are using Snapshot, the DDR is continuously recording data. When the memory is filled,

the oldest data is dropped and the new data is continuously added. When an operating condition

occurs, the DDR puts a marker in the data recording so you can find the exact spot later during play

back. We call this ability to mark data for play back a "trigger". Because driveability problems are

often related to diagnostic codes, one of your choices is to use a diagnostic code as the trigger. You

can choose any code, or a specific code to be the trigger. Or you can trigger the recorder yourself

manually if a suspicious driveability condition occurs.

(b)

It is sometimes helpful to look at data that occurred before the operating condition happened, for

instance, looking for an unnatural trend. It is also sometimes helpful to look at data that occurred

after the operating condition happened. DDR allows you to decide ahead of time how much data

will be retained before, as well as after, the trigger point.

(c)

When you select the Snapshot function, you will see the Snapshot menu selection readout. Choices

include Quick Trigger, Trigger Set-Up, Data Update Rate and Review Snapshot.

SNAPSHOT MODE

XXX FRAMES FREE

SELECTIONS

QUICK TRIGGER

Data Readout Window

NOTE

The second line indicates the amount of frames of memory available to record data.

Although there is no simple way to relate frames to the amount of driving time that will

be recorded, generally a larger number translates into more minutes of recording time

than a smaller number.

(d)

Quick trigger. You will use Quick Trigger to start the snapshot process. If you are using Snapshot

for the first time, selecting Quick Trigger automatically chooses the default operation. This is the

manual Any Numeric Key trigger.

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