Yes, you can attach an external Analog device and change the values just like you change a decimal variable value. You can use "Set Value" or "Ramp" commands in WinScriptLive to adjust the analog output values. For the analog inputs, you can use "Triggers" to start or stop a sequence based on a particular device's incoming variable value.
To setup an analog device, add the device to WinScriptLive just like any other device. Then, when going through the wizard, enter the number of analog inputs or outputs you have.
Once this is device is entered, analog input and output variables will be created for you. These can be accessed by going to the menu "Resources"-->"Analog Inputs" or "Resources"-->"Analog Outputs". From here, you can adjust tolerance and expected voltage levels.
Device Types that have been used previously and that have product files are listed below:
Beckhoff - BK9100+KL3064+KL9010 (4 channels of analog inputs)
Avantech Adam 6017
Beckhoff - BK9100+KL4002+KL9010 (two channels of analog outputs)
Avantech Adam 4024