ABB V18345-1010121001 TZIDC Electro-Pneumatic Positioner

The ABB V18345-1010121001 is an intelligent TZIDC electro-pneumatic valve positioner configured for single-acting (spring-return) actuators with fail-safe function and 4–20mA analog position feedback. In fail-safe mode, loss of signal or power causes the positioner to vent the output pressure, allowing the actuator spring to drive the valve to its safe position. This configuration is ideal for safety-critical applications such as emergency shutdown valves, pressure relief systems, and process isolation in chemical and petrochemical plants.

Q: What is the ABB V18345-1010121001?

A: The V18345-1010121001 is a TZIDC intelligent electro-pneumatic valve positioner configured for single-acting (spring-return) actuators with fail-safe function and analog position feedback.

Q: How does "fail-safe" work on a single-acting positioner?

A: On loss of electrical power or 4–20mA signal, the positioner vents output air pressure. The actuator's internal spring then drives the valve to its safe position (typically fully closed for most safety applications).

Q: How does the V18345-1010121001 differ from the V18345-1010221001?

A: The 1010121001 has fail-safe mode (valve moves to safe position on power loss). The 1010221001 has fail-freeze mode (valve holds last position). The fail-safe variant is preferred for safety instrumented systems and emergency shutdown applications.