Doosan V158TI Operation & Maintenance Manual page 214

System Troubleshooting (Instability)
1. Instability at rapid intervals (hunting): Applying SW D1 and D2
(1) The differential function activates when D1 is placed in the ON position.
(2) This can increase the responsiveness to changes in speed (rpm), thereby enabling quicker response
to changes in speed.
(3) Slight hunting may occur at rapid intervals due to sensitive response to external frequency noise.
In such cases, turn D1 off and readjust the gain and stability.
(4) If the instability persists in spite of doing so, turning off SW D2 on the device can help to stabilize the
engine.
(5) After taking such measures, readjust the gain and stability again in order to optimize the system. This
will help to reduce and eliminate instability.
2. Instability at slow intervals (hunting)
The main factors involved in hunting at slow intervals have many causes but generally, it occurs when tun-
ing is not optimized due to the slight differences in mechanical characteristics in each engine. Such hunt-
ing can mostly be resolved by readjusting the gain and stability within the controller.
IMPORTANT
Refer to the information on the order of adjustment.
3) If the problem is not resolved with the methods above
(1) Loss of control function due to a fault in the controller itself - replace the controller.
(2) Fault in an external mechanical device (actuator, fuel injection device, turbine, etc.) - adjust the
mechanical device.
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