Most of the Panasonic 140 Camera and RP-150 Controller combos are pre-programmed so that the User 6 button activates the wiper on the camera.

But if that is not working, you can manually activate the wiper:

1) Press the Function button on the controller

2) On the touchscreen, tap the "Housing Info" menu.

3) Tap on Row 1

4) To change the Wiper setting, use the F4 knob on the controller to change the Wiper setting to Slow or Fast. Press the F4 knob to save the action. This will now activate the wiper. Use the F4 knob to turn the wiper OFF when you are done.