BSL PRO Software Guide - Biopac

Acquisition Functions 149Chapter 10 MP Menu — Other CommandsThis chapter will cover the MP Menu commands not discussed in the preceding chapters on Setup Channels andSetup Acquisition.Set up TriggeringNot available for MP45Using a trigger allows you to start an acquisition “on cue” from a trigger connected to an analog input channel (CH1to CH4). By default, the trigger is off, and during a normal acquisition, the MP UNIT will begin collecting datafollowing a mouse click the button in the lower right hand corner of the screen. When Set up Triggering isused, acquisition will begin when the established trigger level is reached.To begin an acquisition with a trigger:1) Select Set up Triggering from the MP UNIT menu to generate the Set up Triggering dialog:Set up Triggering dialog box and Source options2) Choose a channel from the Source pull-down menu. You can select CH1, CH2, CH3, CH4 (MP UNIT frontpanel) or an external Trigger (MP36/35 back panel).External Trigger requires a TTL signal from a third-party device such as a stimulator, pump, presentation programor force plate.3) Choose Pos Edge or Neg Edge from the menu to indicate whether you want a positive or negative edge totrigger the acquisition. Look at the nature of the signal to determine which is most appropriate.‣ A Positive edge occurs when the signal begins below the threshold and crosses above it.‣ A Negative edge occurs when the signal begins above the threshold and drops below it.4) Set the Trigger level by keying in a value or by moving the scroll bar to adjust the threshold value.When setup is complete, close the Set up Triggering window and click the button to begin acquisition assoon as the trigger is activated.The dialog box shown above is set to begin acquisition when a level of 25.00 mV is reached on analog channel 4.