Using EScope

EScope starts with a nearly blank screen. To start displaying traces, click the “Run” button. The “LED” will turn bright green. By default, data is acquired from the first two channels of your first DAQ card.

To select which DAQ card to use, click the “Hardware” button. This opens a dialog where you can also set the sampling rate.

To select which channels to display, click the “Channels” button. In the resulting dialog, you can also change scale factors. This allows EScope to display physically correct voltage or current scales when you use, e.g., a 10× probe or are reading from one of the scaled outputs of an AxoClamp amplifier.

On the main screen, you can change the vertical offset of each channel by dragging the handles on the left. You can also change the vertical zoom of each channel by dragging the scale bars on the right. You can change the horizontal zoom by dragging the scale bar below the trace display. Scrolling your mouse wheel while hovering over any scale bar also works.

Triggering

By default, EScope continuously displays the data as they come in. Often, however, it is useful to make display contingent on an external event. For instance, you might have one channel teed to a stimulus marker and another channel record a neuronal response. In that case, the “Trigger” menu allows you to align subsequent traces on an upward or downward transition on a chosen channel. In trigger mode, traces align on the triangle marker below the main screen. This marker can be dragged left or right. Use the “Auto trigger” mode to make EScope pretend it sees a trigger when there is a long time between actual triggers.

Stimuli

To define stimuli, click the “Stimuli” button. This opens the separate Stimuli window.

Saving acquired data

In typical operation, it is most convenient to stream the data to disk as they are acquired. This is achieved by checking the “Capture” button. (Nothing happens unless “Run” is also clicked.) Files are saved in Documents/EScopeData using filenames constructed as YYYYMMDD-HHMMSS timestamps. For every “Capture” there will be three files: one with “.escope” extension that contains the metadata for the recording in json format; one with “.dat” extension that contains the actual data; and one with “.config” extension that contains the full configuration of EScope at the time of recording. The “LED” turns red while actively capturing data.

In addition to recording data continuously, you can also save a single sweep. This is useful if you did not have “Capture” enabled, but some interesting event appeared on the screen. Best to click “Stop” first, to keep a spurious trigger from overwriting the display. Then click “Save Sweep”. This saves a trio of files in the Documents/EScopeData with a sweep number appended to the usual timestamp.

You can see the timestamp and sweep number on the top right of the display, so it is easy to copy these into your notes.

Loading previously saved data

You can reload previously saved data by pressing the “Load Sweep” button. This will load either the single sweep saved by “Save Sweep”, or the final sweep of a longer “Capture”. While this functionality can be useful to quickly inspect a series of saved sweep, for more advanced analysis, it is generally preferably to load data into a separate Python session (or Jupyter notebook) using the escope library.