What is the difference between an automatic levelling system and manual chocks (ramps)?
A manual ramp makes a coarse correction by raising the RV together with the wheel; you have to move the vehicle back and forth on every attempt and the precision obtained is limited to what the eye can judge. An automatic system such as the KTS200 drives 4 12V DC electric legs with an integrated inclination sensor and goes down to 0,025 degree precision. The ramp depends on the vehicle's position, the electric system does not.
The two methods do not do the same job. A ramp/chock goes under the wheel, so it provides a correction only at the point where the vehicle is standing and only by the height of the block. If more than three layers of block are needed, moving the vehicle is the better course.
Automatic levelling, by contrast, works with legs mounted on the chassis. On the KTS200 the ASX103 levelling brain measures the slope on two axes (front-rear and left-right) and the GRV485 control unit drives the 4 legs accordingly. The order is fixed: first the legs come down one by one to find ground contact, then front-rear is corrected, then left-right, and finally in the fine stage it goes down to 0,025 degrees.
- Ramp: cheap, needs no electricity, requires repeated manoeuvring.
- Automatic system: runs from a 12V DC supply, gives a repeatable result with one button, has Wind and Fine modes.
The important common rule applies to both methods: do not lift all the wheels off the ground. The legs do not replace the parking brake; the handbrake is applied and wheel chocks are used. On very sloping ground, using a ramp together with the automatic system means the legs use up less stroke.
The full topic: RV automatic levelling guide