Technical Specifications

FAQ

1. What is the ABB V18345-1020520001 used for?

The ABB V18345-1020520001 is a TZIDC-series intelligent electro-pneumatic valve positioner designed for pneumatic control valves and actuators used in industrial process control systems. It receives a 4–20 mA command from the control system and combines this signal with actual valve-position feedback to continuously correct the actuator position. This allows the valve to remain at the position requested by the control system. The positioner can be used in flow, pressure, temperature, and level control applications and can serve as the valve positioning device within PLC- or DCS-based control loops.

2. Does the V18345-1020520001 support HART communication?

Yes. The V18345-1020520001 supports HART digital communication in addition to its conventional 4–20 mA control circuit. A compatible HART communication device can be used to access supported parameters, operating information, and diagnostic data. HART communication is particularly useful during commissioning and maintenance because technicians can review positioner information without relying solely on local inspection. It can also simplify troubleshooting when the positioner is installed in a difficult-to-access location.

3. What types of actuators can be used with the V18345-1020520001?

The positioner is suitable for compatible pneumatic linear and rotary actuators. Linear actuator applications require a feedback mechanism capable of accurately detecting linear movement, while rotary actuator applications require mounting and feedback components designed for angular movement. The feedback mechanism must be correctly aligned with the actuator’s direction of travel. Excessive mechanical backlash, incorrect adjustment, or loose connections can cause the feedback signal to differ from the actual valve position, even when the positioner’s electronic control system is operating normally.

4. How does the V18345-1020520001 perform automatic valve positioning?

The positioner uses closed-loop control to automatically regulate the valve position. The control system sends a target position command, while the positioner continuously monitors the actual actuator position through its feedback mechanism. If a deviation exists between the target and actual positions, the internal controller adjusts the pneumatic output and moves the actuator toward the required position. As the actual position approaches the target, the output is continuously corrected to maintain stable positioning. This allows the positioner to compensate for normal changes in actuator load, valve conditions, and certain process disturbances.

5. How should a valve-position deviation be diagnosed on the V18345-1020520001?

First, verify that the 4–20 mA input signal is stable and that the control system is sending the correct command. Next, check the instrument-air supply and make sure the pressure is stable and the pneumatic tubing has no significant leaks. The mechanical feedback mechanism should then be inspected for looseness, binding, excessive backlash, or incorrect adjustment. If these areas are satisfactory, review the positioner’s configuration and commissioning status. Persistent positioning errors may also be caused by excessive valve-stem friction, insufficient actuator force, mechanical obstruction, or excessive process forces acting on the valve.

6. How should the V18345-1020520001 be commissioned after installation?

After installation, first verify that the mechanical connection between the positioner and actuator is correct and that the feedback mechanism follows the actuator throughout its travel. Connect the instrument-air supply and check the pneumatic circuit for leakage. The 4–20 mA control signal should also be checked to confirm correct wiring and signal integrity. Configure the positioner according to the installed valve and actuator arrangement, then perform the appropriate automatic adjustment procedure. After commissioning, operate the valve through its complete range and check movement direction, position feedback, positioning response, and control stability. For PLC or DCS installations, confirm that the control system also receives the expected valve-position information.

7. Why might the valve oscillate or move frequently around the target position?

Valve oscillation can be caused by unsuitable control parameters, mechanical feedback problems, pneumatic instability, or mechanical characteristics of the valve. If the positioner’s control sensitivity is not properly matched to the actuator and valve, the actuator may repeatedly correct its position around the target. Mechanical backlash in the feedback linkage can create a changing position signal, while unstable instrument-air pressure or pneumatic leakage can produce inconsistent actuator movement. Excessive actuator friction can also contribute to unstable positioning. Troubleshooting should begin with the input signal, air supply, feedback mechanism, and valve mechanics before adjusting control parameters.

8. What should be checked when replacing the V18345-1020520001?

Before replacement, verify the complete model number and make sure the new positioner is compatible with the existing actuator, valve, control signal, and mounting arrangement. Before removing the original unit, record the electrical wiring, pneumatic connections, feedback mechanism, and important configuration parameters. After installation, check the mechanical linkage and feedback direction, then verify the pneumatic supply and 4–20 mA loop. Configure the replacement positioner and complete the required automatic commissioning procedure. A full valve-travel test should then be performed to confirm that the actual position follows the control command correctly. If HART communication is used, verify communication and diagnostic information as well. Final testing should confirm stable positioning, correct response, and reliable operation under normal process conditions.