BSL PRO Software Guide - Biopac

Acquisition Functions 139REFERENCES TAB (OUTPUT PREFERENCES)Reference ChannelSS58L onlyChannel AssignmentThis option allows you to “Monitor” the output signal on one of the analog or digitalinput channels without making any physical connections. This is an internal,hardware/firmware, feature that recreates the output signal and allows recordingin “real time.” The assigned reference channel will override any “real” input signal.For example, if a transducer is connected to CH 1, and CH1 is chosen as thereference channel, then the signal coming from the transducer will not beviewable, and will not conflict with the reference signal generated internally.The reference signal is not the real signal, but is a very accurate “estimate” of thereal signal. The pulse timing accuracy will be within 100 microseconds. If ananalog input channel is used as the reference channel, the pulse level will beaccurate within 5%. If the SS58L encounters a load that reduces or distorts thepulse output, the reference signal will not reflect this amplitude distortion.If a digital input channel is used as the reference channel, only a digitalrepresentation of the pulse will be generated. In other word, regardless of thepulse level, when no pulse is occurring, the level will be 0 Volts, and when thepulse is occuring, its level will be shown as +5 Volts.Use the pull-down menu to choose which analog or digital input channel will be used asthe output reference channel.When a new reference channel is assigned, a warning will be generated to alert you thatthis setting will overwrite the existing Channel Setup parameters for the selected channel.For example, if you set up CH1 for ECG data and then select CH1 for the ReferenceChannel, your ECG parameters will be replaced. If you then select another channel, CH1will be restablished with the default analog input parameters, and you would need torecreate your ECG settings (by using Presets or manual entry).The reference Channel label should read: “Low Voltage Stimulator - Reference Out”.When an Analog Input Channel is assigned as the Reference channel, that channel, asviewed from the MP UNIT>Set up Channels dialog, will be in a “Lock-Out” mode. Thismeans that the Preset pull-down menu icon for that channel will be grayed (inactive). Theassigned reference channel will be inactive for “real” inputs until the Reference ChannelPreference is changed to “None” or another channel. The wrench button, when pressed forthe Reference channel, will still allow viewing of the channel parameters, but all entryboxes and pull-down menus will be inactive.When a “Low Voltage Stimulator” control panel using an assigned Reference channel isclosed, the channel that was assigned as the reference channel will be removed from“Lock-Out” and will automatically change to the default, “CH X Input” settings. Thereference channel assignment will be saved in the template or data file, so that if the “LowVoltage Stimulator” control panel is reopened, the reference channel will be automaticallyre-assigned, without any warning prompt given.