Grand Master Fader
Given a hypothetical grand master fader that can be controller with the continuous controller 13 (assuming for the sake of this example that your device is also set to receive on MIDI channel 1), you can send the message 176 13 127 to a midiout object to turn the fader up to full. Another way to do this would be to use a ctlout object, send the number 1 in the right inlet, the number 13 in the middle inlet, and then send 127 in the left inlet. To create a continuous fade, send successive messages with gradually changing slider position values.
(Double-click on the midiout or ctlout object and make sure that it’s addressing the correct device, then set the correct MIDI channel, then move the slider.)