Creating an AcqKnowledge template

Last modified by Iris Spruit on 2023/12/18 17:01

Introduction

When recording physiological signals with the BIOPAC system, the AcqKnowledge software needs to be set-up. This set-up is consolidated in a template. The most important settings in a template are the to be recorded signals and the channels in which the signals are to be recorded, the sampling rate, and markers. Other settings include toolbar buttons and event marking hotkeys. A template is created once and used for each recording so that the settings are the same for all recordings.

Short manual

Note that the steps below are for creating a template in AcqKnowledge up to version 5.0.2. In later versions, the modules can be added in a different (easier) way.

In the example below we’ll add one module and we set up the marker channel. Markers can be sent from stimulus presentation software (such as E-Prime) through the parallel port. This allows for 8 bits of data to be sent (i.e. values 0 to 255). See Markers and Events for more information.

Start AcqKnowledge

Make sure you have your BIOPAC hardware

Start AcqKnowledge

Select Create/Record a new experiment and Create empty graph and click Ok

 

AcqKnowledge should start with the Data Acquisition Settings window opened. If not, go to MP150/MP160 and Set Up Data Acquisition

Add modules

A BIOPAC system typically consists of a MP150/160 unit, an STP100C, HLT100C, UIM100C and one or more physiological modules (such as the ECG100C for measuring ECG). To record the corresponding signal, each physiological module should be added to the template. The instructions below show how to add a 100C series module, instructions differ slightly when adding a BioNomadix or Smart amplifier module.

In the Analog tab hit Add New Module to add modules (open by default).

Select the module you want to add. The module type is written on the physiological module itself. For example, add ECG100C (ECG100C and ECG100C-MRI).

Next, you’ll need to select the channel. The channel switch is located on top of the physiological module (note that this only applies to the 100C series).

Next, the configuration of the module needs to be set (gain and filters). These settings should be the same as the settings on the module itself. See other documentation for more information about the settings.

Once the module is added, specify the Label (e.g. “ECG”).

When you want to modify the settings of the module, for example when you changed the settings on the physiological module itself, click on the wrench icon to open the settings dialog again.

When you add a module which requires calibration (such as EDA/GSR), make sure to check the first checkbox under the green icon. This check will force the module to be recalibrated on the start of data acquisition, which prevents uncalibrated data when templates are reused. Acq-calibrateEDA.png

More Analog, Digital, or Calculation channels can be added. See for example here for more information on adding a marker channel that processes markers sent through parallel port to the Biopac system. Note that adding a marker channel is not required when making a template, however, event marking the data in some way is strongly recommended (see here for more information about events and markers). Alternatively, it is possible to insert events using hotkeys (see below), or by using Network Data Transfer.

Set sampling rate and recording length

In the menu at the left side, select Length/Rate

It is recommended to select Record and Append using Memory. With the Append setting data is appended to the file each time a recording is started. Other settings overwrite already existing data. With the Memory setting the data is stored in the computer memory during acquisition. Storing to Disk is not recommended as disk reading errors could cause AcqKnowledge to crash. Storing to the MP150/160 memory is also not recommended as storage space is very limited.

Select the Sample rate (i.e. the number of samples are recorded per second). In general, SOLO recommends using a sampling rate of at least 1000 Hz, or at least 2000 Hz when EMG is included. Choose the highest needed for your acquisition set-up. Note that the higher the sampling rate, the larger the data file will be. When setting up the sampling rate here, this sampling rate is used for all channels, which is recommended. It is however possible to have different sampling rates for each channel.

Set the Acquisition Length. By default it is set to 30 minutes, which is usually not enough.

Set up event hotkey(s)

Setting up one or more event hotkeys can be useful. When such a hotkey is pressed during recording, an event is created at that moment in the recording. If desired, a message can then be entered which accompanies the event. This can be particularly useful in observational studies. Note that it is not required to set up hotkeys.

In the menu at the left side, select Event Marking

Select a desired Hotkey (Escape or F1 through F9).

Select Insert Event under Action

A Type of event can be selected. The Default Type is usually sufficient.

It is possible to insert an event into a specific channel (e.g. in the ECG channel only), or insert events globally (in which case the events are not bound to a specific channel). When unsure, set Channel to Global.

For Label there are two options:

  • Fixed: provides a fixed label from text entered into the label field to the right. This label is used every time the assigned hotkey is pressed.
  • Sequential: labels for events will iterate sequentially through the entries in the table when the assigned hotkey is pressed. The area under ‘Label’ is editable for entering text.

Include time can be checked to include a time stamp in the label (note that this will create dissimilar labels per participant).

Include date can be checked to include the date in the label (note that this will create dissimilar labels per participant).

Customize toolbar buttons

It can be very useful to include specific buttons into the toolbar in your template. This way, you do not have to specify which buttons you want to show or hide each time you start a recording. By default, the toolbar does not include a lot of buttons. It is advised to add some in the template. Below a few handy buttons, but try them out yourself to see which ones might be useful for you.

When clicking the -+ button some useful options appear:

  • Scaling Toolbar – includes some handy scaling buttons, such as autoscale horizontally or vertically, or both.
  • Display Mode Toolbar – It is possible to view your data in different ways. Usually, the chart mode is used, which displays the waveforms stacked on top of each other. The Scope mode plots the waveforms in one graph, which allows for waveform comparison.
  • Measurements – Can be useful when inspecting your data. Select a part of your data to obtain metrics that apply to the selected part. The metrics can be selected in the drop-down menu’s.
  • Journal – to show the journal at the bottom of the window. Can be used for notes. Info can also be put in the journal and saved with the template (e.g. instructions for the experimenter, important reminders).
  • Hardware – Makes it possible to select which hardware (MP150/160 system) the computer is connected to. Useful when multiple systems are used in the same lab.
  • Event bar – Shows event label.
  • Channel buttons – allows you to show and hide channels (Alt + click on a channel number to hide or show the channel

Save template

When done creating the template:

  • Go to File and Save as
  • Enter a file name
  • Save as type Graph Template (*.gtl)
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