For safety reasons this control panel has a locking function. To activate/cancel this function, follow the “Part 3-Custom Programming Guide: To Change the Screen Lock Function” in the instructions available in the link below.
1. To lock the control, press “M” for 3 seconds. If the control is locked, only a bar “---“ is lighting in the display and any operation is invalid.
2. To unlock the control, press “M” for 3 seconds. The height will be shown in the display. The control will be active for 1 minute but when there are no activations made within 1 minute, the control will go in to locking mode again with the locking function on.
See the full instructions here
Or watch the video: