1. Sumitomo excavator rotation speed limit control loop
This control loop is used to control the slewing speed that rises as the flow of the hydraulic pump increases (only in SP mode).
In the single-turn operation, according to the input electrical signals of the rotary pilot pressure sensor and P1 pressure sensor, the signal is output from the controller to the proportional valve for P1 flow control of the hydraulic pump.
The hydraulic oil discharged from the hydraulic pump A3 is distributed to the P flow control proportional valve and output from the controller to the PI flow control proportional valve signal to reduce the hydraulic oil flow on the side of the hydraulic pump A1 to 200 L/min.
① Fully-automatic conditions for the rotation speed limit control:
①Single rotation full joystick operation;
② Walking non-operation;
③ Operating mode SP.
Conditions for releasing the swing speed limit control:
①When performing the operation of the upper body except for the boom lowering → slowly release (reduce the impact):
②When walking operation → immediate release (avoid snake walking);
③When performing backup operations.
2. Rotary overflow cut-off control loop
When the single swing operation is suddenly performed, the starting pressure will rise, and the remaining oil will be discharged from the overflow valve of the swing motor.The function of this control circuit is to control the remaining oil discharged to a minimum by controlling the hydraulic pump, so as to achieve energy saving Effect.
