Product Overview

The ABB V18345-2021221001 TZIDC Valve Positioner is part of the TZIDC family of intelligent electro-pneumatic valve positioners used to control the position of pneumatic control valves in industrial process systems. It receives a control command from the automation system and regulates the pneumatic actuator so that the valve reaches and maintains the required position.

The positioner is installed at the valve and works as the interface between the control signal, pneumatic actuator, and valve stem or shaft. During normal operation, the positioner compares the commanded valve position with the actual valve position and adjusts the actuator air accordingly. This closed-loop arrangement allows the control valve to respond to changing process requirements rather than relying on an open-loop pneumatic signal alone.

The TZIDC platform is suitable for applications where accurate valve positioning and continuous process control are required. It can be integrated into process automation systems controlling flow, pressure, temperature, and other process variables through pneumatically actuated valves.

Technical Specifications

Product Features

• TZIDC intelligent valve positioner for pneumatic control valves.
• Provides closed-loop control between the commanded and actual valve position.
• Interfaces directly with pneumatic valve actuators.
• Suitable for continuous process control applications.
• Supports accurate regulation of valve movement during changing process conditions.
• Can be integrated into plant-level process automation architectures.
• Useful for control valves regulating flow, pressure, temperature, and related process variables.
• Suitable for maintenance and replacement of existing ABB TZIDC installations.

Working Principle

The V18345-2021221001 receives a valve position command from the process control system and converts that command into controlled pneumatic actuator movement. The positioner continuously monitors the actual valve position through its mechanical or position-sensing interface.

The internal control loop compares the requested position with the measured valve position. When a deviation is detected, the positioner adjusts the pneumatic output to the actuator, increasing or reducing actuator movement as necessary.

Control command → TZIDC positioner → Pneumatic actuator → Control valve → Position feedback → TZIDC positioner

Once the actual valve position approaches the commanded value, the pneumatic output is adjusted to maintain the required position. This feedback process allows the valve to follow changing process commands while compensating for variations in actuator behavior and process load.

Role in a Process Control Architecture

The ABB TZIDC positioner operates at the final-control-element level of a process automation system. The controller determines the required valve position based on the process-control loop, while the positioner handles the local closed-loop positioning of the pneumatic valve.

Industrial Applications

Installation and Maintenance

1. Verify the positioner model and valve assembly before installation.
2. Confirm that the positioner is mechanically compatible with the pneumatic actuator.
3. Isolate the process and pneumatic supply before removing an installed positioner.
4. Inspect the valve linkage and mounting hardware for wear or mechanical damage.
5. Connect the control signal according to the applicable system configuration.
6. Ensure pneumatic supply connections are clean, secure, and free from leakage.
7. Confirm that the position feedback linkage moves freely through the complete valve travel.
8. Perform the required initialization or calibration after installation.
9. Check valve travel against the commanded position during commissioning.
10. Inspect pneumatic tubing and fittings periodically for leakage or deterioration.
11. Monitor position deviation, response behavior, and diagnostic indications during operation.
12. When replacing the positioner, verify the valve, actuator, feedback linkage, and control-system configuration before returning the loop to service.

Related Components

Recommended Related Models

Key Advantages

• Provides closed-loop positioning for pneumatic control valves.
• Combines electrical control commands with local pneumatic actuator regulation.
• Suitable for continuous process-control applications.
• Supports accurate valve movement through position feedback.
• Integrates into PLC and DCS-based process automation architectures.
• Applicable to a broad range of industrial fluid-control processes.

Technical FAQs

What is the main function of the ABB TZIDC valve positioner?

Its main function is to regulate a pneumatic valve actuator so that the valve reaches and maintains the position commanded by the process control system. It uses position feedback to correct deviations between the requested and actual valve positions.

How does the TZIDC positioner differ from the pneumatic actuator?

The pneumatic actuator supplies the mechanical force needed to move the valve, while the TZIDC positioner controls the pneumatic output supplied to the actuator. The positioner therefore manages how far and how accurately the actuator moves the valve.

What should be checked when replacing a TZIDC positioner?

The replacement should be checked for compatibility with the valve actuator, mechanical mounting, feedback linkage, control signal, pneumatic connections, and control-system configuration. Calibration or initialization should also be performed after installation.

Why is position feedback important in a control valve loop?

Position feedback allows the positioner to determine whether the valve has actually reached the commanded position. Without this feedback, the system would have less ability to correct mechanical or pneumatic deviations that affect valve travel.