BSL PRO Software Guide - Biopac

Acquisition Functions 79Chapter 6Set up AcquisitionsOnce you have selected the channels to be acquired, the next step is to set up the acquisition parameters under the MP UNITmenu. Among other things, these options control where data will be stored during an acquisition, the sample rate for datacollection, and the duration (length) of each acquisition. The dialog box that allows these options to be set is generated via Setup Acquisition under the MP UNIT menu. You must establish acquisition parameters prior to pressing the “Start” button. TheMP UNIT > Setup Acquisition menu item is inactive (grayed) during acquisition.Data storage optionsThere are three pull-down menus at the top of the Set up Acquisition dialog that allow you to control how and where theacquisition data will be saved.1) Record/Record last controls whether the software saves all the data or only the most recent segment.‣ Record will store data for the amount of time specified in the acquisition Length box. This is the default and isappropriate for almost all types of acquisitions.‣ Record last will acquire data continuously, but store only the most recent segment of data (equivalent to the durationin the acquisition Length dialog box). That is, if the value in the acquisition Length box is 30 seconds and Record lastis selected, data will be acquired data ad infinitum, but BSL PRO will store only the most recent 30 seconds of data.2) Save once/Autosave file/Append allows you to vary how the data is saved to a file. By default, BSL PRO will appendacquisition data to a single continuous file.‣ Save once will begin an acquisition when the button is clicked and will stop acquisition either when theacquisition Length has been reached or when the button is clicked.‣ Autosave file enables you to perform several acquisitions one after another and save the data from each acquisition ina separate file.When Autosave file is selected, a button will appear by theSample Rate entry box. Clicking on the File… button generates an“Autosave File Setup” dialog that prompts you to choose the root filename for the data from each acquisition.Append allows you to pause the acquisition for arbitrary periods. Append markers are automatically inserted to indicatewhere each appended acquisition segment begins. (See page 172 to customize append markers and/or preset marker labels.) TheAppend mode is unique in that clicking on the button only pauses the acquisition, which can then be restarted byclicking on the button. This can be helpful when recording only a few key events that will occur randomly over a longperiod of time, since it will reduce data storage and transformation processing.When Append is selected, a Reset button is generated in the Setup Acquisition dialog. Clicking on the Resetbutton erases the acquired data file and “continues” the acquisition. (This is essentially the same as saying yes to an“Overwrite existing data?” prompt.)