The TZIDC electro-pneumatic positioner mounts to pneumatic linear or rotary actuators. The new positioner from ABB Instrumentation is designed for 4-20mA control systems. The positioner automatically adapts its control settings to final control elements, such as valves, offering optimal control behavior. Modularity permits future enhancements by various optional retrofits and plug-ins. An I/P module within the TZIDC positioner adjusts a 3/3-way valve that regulates airflow for pressurizing or depressurizing the actuator to maintain position. When the actuator reaches the position set point, the 3/3-way valve closes in its center position to minimize air consumption. The positioner comes in four different pneumatic versions: single-acting or double-acting actuators, each with a “failsafe” or “fail-freeze” function. It has a built-in operating panel providing a two-line LCD and four pushbuttons for optimal local configuration, simple commissioning, and operational monitoring. TZIDC models are available with direct serial communications, as well as HART, Profibus PA, and Foundation Fieldbus protocols.
