BSL PRO Software Guide - Biopac

70 Part CAnalog Input channels are the most common type of channel and are used to acquire any data with “continuous” values.Examples of this include nearly all physiological applications where input devices (transducers and electrodes) produce acontinuous stream of varying data. The range of values for analog channels is typically in the range of ±50 mV, althoughvoltages as high as ±50 V can be measured with BSL PRO. BSL PRO records and displays up to four analog signals fromdevices connected to the analog input ports on the front of the MP UNIT Acquisition Unit.Digital Input channels (MP36 or MP35 required), in contrast to analog input channels, are designed to collect data from asignal source with only two values (0 and 1). This type of data can be useful in recording whether a switch is open or closed, andascertaining if a device is on or off, as in reaction time studies or control applications. Input values for digital channels have twovalues, +5 Volts and 0 Volts. The MP36/35 interprets +5 Volts as a digital 1 and interprets 0 Volts as a digital 0. Since digitalchannels have a fixed value, the parameters and scaling options are disabled for these channels. The main function of digitalchannels is to track on/off devices such as push-button switches and/or to receive digital signals output by timing devices.Similarly, these channels are also used to log signals from devices that output auditory/visual stimulus for examination ofstimulus response patterns. BSL PRO records and displays up to eight digital signals from devices connected the I/O port on theback of the MP36/35 acquisition unit.+5 volts(binary "1")0 volts(binary "0")Positive edgeNegative edgeDigital Input Channels Have a Fixed ValueCalculation channels transform incoming data in some way (rather than collect external data as input channels do). The originaldata is not altered — it is just stored in a modified form on a new channel. You can use Calculation channels to compute a hostof new variables by using transformations (such as BPM, integration calculations, and math functions).Up to 12 Calculation channels can be acquired. You may use the output of one Calculation channel as the input for anotherchannel, as long as the output channel has a higher channel number than the input channel. In other words, it is possible forCalculation channel 3 to include the result of Calculation channel 1, but not the other way around. This allows for complexCalculations to be performed that involve two or more Calculation channels, such as filtering ECG data then computing BPM.Each Calculation channel acquired will reduce the maximum possible sampling rate and increase the amount of memoryrequired to store data both during and after an acquisition. Thus, you may want to consider performing some of these functionsafter the fact if high sampling rates are needed for your particular application.Notes: Calculation channels are OFF by default. To turn a Calculation channel on, click the Presets buttonfor that channel and make a selection from the menu. TIP All of the calculations that can be performed online can also be performed after an acquisition hasbeen completed. These options are available under the Transform menu.Visit the online support center at www.biopac.com