Instruction manual

2 Acquisition 15
The dialog boxes (Figure 2-2 on page 15) show the options for starting the
recording process for both groups of hardware.
Figure 2-2: The DataTrax2 Start dialog boxes
User The easiest away to start the recording is for the User to manually press the Record button in
the upper right hand corner of the DataTrax2 Main window. User is the default setting in
DataTrax2. Recording begins when the User presses the Record button, and will continue until
one of the Stop conditions is met. Pretriggering is not possible in the User (manual) mode.
Timed If desired, the recording of data can be delayed for a user specified fixed duration.
External Trigger Sometimes, it is necessary to synchronize the beginning of the recording with the beginning of
an external event. The DataTrax2 software can be configured to start recording when the WPI
hardware detects a voltage pulse (+3 to +5V amplitude) through the BNC connector of the
Trigger input. Many devices have Trigger or TTL outputs that are capable of starting the
DataTrax2 recording software; these devices include: stimulators, relays, pumps, valves and
cameras.
Triggered from
Channel
For various reasons, data recording may not need to begin until the data itself reaches certain
criteria. For example, it may be necessary to record an animal’s body temperature only if the
base temperature exceeds 100°F. The DataTrax2 software could be programmed to begin
recording when the data on the temperature channel exceeded 100°F. Thresholds above and
below a certain data value can be set to start the recording.
Open the Preferences dialog window from the Edit menu. Click on
the tab for the Channel page. Pull down the Start Mode menu and
select the channel (Ch) that contains the data to be used as a
trigger. Set the values that the data must meet before recording is
triggered. The diagram demonstrates that DataTrax2 is programmed
to look for a trigger from the data on Channel 1 when the amplitude
of the data is above 1.5V and below 2 V.
Pretriggering When an External Trigger or a trigger from a data channel (Ch)is
used, the data just before the trigger occurs may be important to
record as well. For example, if the R wave is used to trigger the
recording of an ECG, the P wave and other parts of the ECG that
occur before the R wave can be recorded. The Pretrigger feature of
the DataTrax2 software can be used to look back in time and display