The system drops to idle by itself — what could be the cause?
The most frequent cause is supply instability: a loose chassis ground, a corroded terminal, insufficient cable cross-section or a weak battery. On the GS740-3P an independent watchdog works with a timeout of approximately 2 seconds; which position is taken is not declared in the product data. The current limit and the mechanical stall protection can also lead to similar behaviour.
Order of checks:
- Supply: measure the voltage at the red and black terminals while the actuator is moving. If the drop under load is large, increase the cross-section, clean the chassis ground point and connect directly to the battery or the main bus.
- Sockets: make sure you have seated the IP67 sockets fully by turning them; a half-seated socket gives intermittent contact with vibration.
- Signal: a broken or intermittent contact at the potentiometer wiper terminal makes the command look like it has been zeroed. Check the integrity of the green pot GND terminal.
- Strain: a jammed cable can cause the current limit (factory setting approximately 7A) to be reached.
On the GS740 there is one more situation: a short press of the button toggles between idle and the stored work speed. The button being triggered by vibration or by cable contact also looks like dropping to idle by itself; route the button cable separately and fixed.
Full topic: Electronic speed and throttle control on diesel engines