Recording Experimental Signals > Creating Stimulus Protocols > Global Stimulus Variables
The amplitude and duration of waveforms within a stimulus protocol can be defined in the waveform parameter tables using the global stimulus variables (G1 .. G5) instead of fixed values. This allows multiple waveform settings within a protocol or related set of protocols to be changed by editing a single value. Global variables are stored independently of individual protocols and applied to all protocols referencing them when the protocol is run.
A waveform parameter can be linked to a global variable by entering the name of one of the five variables (G1, G2, G3, G4, G5) into the field in the parameter table.
The values of the global variables can be set in the table on the Global Variables page. Changing the value of the variable in the global variables table changes the waveform parameter in the protocols which reference that variable.
Note that the units of the global variables applied to waveform duration parameters are seconds (rather than msecs as in the protocols) and for amplitude parameters the units of the stimulus type.