Inconsistent remote and local display for valve actuators
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For the FISHER DVC200, the local display shows an opening degree of 99% while the upper-level display shows 102%. By removing and reconnecting the core wire on the DVC2000, the readings on the local and upper-level displays become consistent again. However, after one or two months, the issue of inconsistent opening degrees reoccurs. What is the cause of this?
The most likely causes for the situation you described are as follows: 1. **Poor contact of the signal wires or oxidation/loosening of the connection terminals:** The fact that things returned to normal immediately after disconnecting and reconnecting the wires at the DVC2000 suggests that the problem lies in the terminal connections. Unstable signals can be caused by factors such as oxidation, rust, or loose connections. 2. **Signal interference or grounding issues:** Interference with the signal or poor grounding of the equipment can cause abnormal readings on the host computer. 3. **Internal failure or drift in the actuator position feedback module:** Wear of the internal feedback components in the DVC2000 or aging of its components can lead to periodic drift. 4. **Quality issues with long-distance transmission cables:** If the signal transmission cables are long, of average quality, or if their path is subject to electromagnetic interference, signal distortion and deviation may occur over time. In light of the above points, it is recommended to carry out troubleshooting in the following manner: – Check, retighten, and clean the terminal connections ； - Verify the specifications for laying the connection cables between the control cabinet and the actuators; use shielded cables when necessary and ensure proper grounding ； - Verify the status of the internal components of the DVC2000, such as whether the feedback potentiometer or sensors need to be replaced ； - Check the grounding of the circuits and instruments to ensure that they meet the specified grounding requirements. Generally speaking, the phenomenon you described is most likely caused by poor contact of the signal wires, oxidation, or wiring interference; it is advisable to first check the connections of the wires and terminals before considering issues within the device itself. .
Measure the output current; once the mA value corresponding to a loose potentiometer has been determined, use a signal generator to create a loop at the system side in order to verify the accuracy of the card. If everything is fine, then we will investigate other possible causes.
Well, it’s very likely the third reason