Replacement plan for displacement sensors

Replacement plan for displacement sensors

according toThe replacement method provided by Guangzhou Zhongxin requires multiple full opening and full closing of the control valve to adjust the zero and full position of the valve control card (VCC card). Adopting this method is bound to bring significant sudden changes in the load of the unit, seriously threatening the safe operation of the unit. In practice, through multiple experiments, we have summarized an effective set of ten thousand methods, which will not cause disturbance to the load of the unit. The method for replacing displacement sensors online is briefly described as follows:

(1) The unit has exited the coordinated operation mode. Because in a coordinated manner, CCS treats the four high voltage control valves of DEH as one actuator, artificially changing the opening of a certain high voltage control valve can cause the system to mistakenly believe that the control valve is operating, thereby causing other control valves to follow suit. Causing load fluctuations.

(2) DEH is put into the power circuit, and the relief valve of the regulating valve is manually opened (the displacement sensor of the regulating valve is faulty). The hydraulic motor of the regulating valve loses oil pressure and automatically closes, and the regulating valve will not act with changes in servo valve commands.

(3) When connecting the new sensor to the terminal board of the VCC card, it should be noted that the wiring should be done in the order of 3-2-1, and the disassembly should be done in the order of 1-2-3. Otherwise, false valve positions (displayed as maximum opening) may occur. If the coordination mode is not exited, it will cause significant disturbance to the regulating system.

(4) Manually move the iron core of the sensor, simulate the full stroke switch of the regulating valve (such as a high-pressure regulating valve with a stroke of 4Omm), and adjust the zero position and full scale of the VCC card to 0-4V according to the servo system debugging diagram.

(5) After the adjustment is completed, install the sensor on the regulating valve, manually send a 0% closing command to the regulating valve, and then manually close the relief valve of the regulating valve to ensure that the regulating valve does not suddenly open; Manually issue an opening command to the control valve, increasing it by 3% each time to gradually open it. When the command is increased to 50%, adjust the bias of the VCC card to ensure that the difference between A-P meets the requirements.

This method has been successfully applied multiple times in our company's cases, timely eliminating defects, meeting the requirements of unit load adjustment, and ensuring the output of the unit.