ADInstruments POWERLAB TEACHING SERIES Owner's Manual page 28

Choosing a Stimulus Type
The Stimulator only off ers the Isolated Pulse stimulation mode. This generates a
rectangular pulse stimulus that starts at zero current, is raised to the set current
amplitude for the set pulse width (duration), and then falls to zero current again. By
default, the stimulator is off and the current amplitude is set to zero.
Creating a Custom Stimulus Waveform
In LabChart, you can:
Click Custom... to display the Waveform Customization dialog. Further details about
using this dialog are available in the LabChart Help.
Setting Stimulus Parameters
You use the text boxes and sliders to set values for the stimulus parameters. In
LabChart, you can use the Settings dialog for each parameter to configure the range of
values available to the parameter text box and slider controls. Using suitable values can
improve the precision of control over the stimulus parameter when using the slider and
spinner controls.
In LabChart, the following stimulus parameters can be set:
Start Delay: the wait time before stimulation is delivered, once the stimulus waveform
has been started.
Repeats: the number of times the stimulus waveform is repeated, once started.
Max Repeat Rate: the maximum frequency with which the stimulus waveform is
repeated (either 0.1—20 Hz or 6—1200 /min), or the interval between each pulse start
(0.05—10 s).
Pulse Width: the duration of each pulse. The pulse duration is restricted to the range
from 50 μs to 200 μs for safety reasons.
Current: the amplitude of the stimulus current (0 to 20 mA).
End Delay: the wait time at the end of a stimulus segment, aft er which the next segment
is delivered. This is not the same as a Delay segment.
Marker Channel
If you choose a channel from the Marker Channel pop-up menu, then the start time of
a stimulus pulse is marked by a small data spike (this adds to any data in that channel).
The Stimulator Panel
Once you have set up stimulation using the Stimulator dialog, you can easily start or
stop stimulation or change settings while sampling, by using the Stimulator Panel.
Choose Stimulator Panel from the Setup menu to open it
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• Specify whether parameter controls are displayed in the Stimulator and
Stimulator Panel dialogs.
• Define a sequence of segments to create a custom stimulus waveform.
PowerLab Teaching Series - Owner's Guide