Why does hydraulic motion stop instantly when the Emergency Stop button is pressed?
The HCT400 and HCT402 joysticks have an Emergency Stop button. When the button is pressed, the control command is cut; the servo motor moves the lever to the safe center position and oil flow to that lever stops. Since the system is already designed to treat the absence of a signal as a loss within 250 ms, the stop occurs as soon as the command is cut.
Emergency Stop is not a mechanism that cuts hydraulic flow with a separate valve; it is a function that stops driving the lever. When the lever returns to the neutral position, the valve goes to neutral and oil flow in that line stops.
Sequence of operation:
- The button is pressed and the remote control's control output is cut.
- The motor moves the lever to the safe center position.
- Since the valve is in the neutral position, oil flow stops and motion ends.
This reaches the same safe state as the signal loss behavior: in both cases the target is the neutral position of the lever.
Know its limits: Emergency Stop stops motion, it does not lower a suspended load and does not take over load holding. What keeps the load suspended is the load holding / counterbalance valve already present in the hydraulic circuit, and this valve must be mounted directly on the cylinder port. In addition, Emergency Stop does not replace the vehicle's main power disconnect or PTO disengagement function; the operation's existing emergency procedures remain valid.
Full coverage of this topic: What Does the HCT402 Achieve, How, and How Much? A Technical Review