Fail-Safe Neutral
This is the actuator leaving the hydraulic lever in the neutral position that stops oil flow in the event of a fault, a supply interruption, or loss of communication. When the lever returns to neutral, no flow reaches the cylinder and the implement neither rises nor lowers. On wireless-controlled retrofit kits this behaviour is the step that follows immediately after timeout protection.
In an open centre hydraulic system, while the control lever is in neutral the pump flow returns to the tank and no pressure builds up in the system. That is why the "safe" state is not closing the lever but bringing it exactly to neutral; a lever left half open produces a slow, unnoticed movement.
- When it engages: on loss of communication, when emergency stop is pressed, at critical battery level, or when the board detects a fault condition.
- How neutral is known: from the mid reference point taught during calibration. If calibration has not been done, the system cannot know where neutral is.
- Return: when the fault is cleared the implement does not move on its own; the operator is expected to give the command again.
In the field this translates as follows: if the remote's battery runs out or you go out of range, the load stays suspended in the air but does not descend uncontrolled. The HCT400's 250 ms signal loss protection triggers exactly this transition. Even so, the hydraulics are not to be trusted while working under a raised hitch; mechanical support is used.
The context in which this term is used: Converting a tractor hydraulic lever to electronic control