Application area

The TZIDC is an electronically configurable 2-wire 4 to 20 mA valve positioner with HART® communication capabilities designed for

mounting on pneumatic linear or rotary actuators.

The TZIDC-200 is a variant designed with a flameproof enclosure as explosion protection concept.

The integrated I/P module with subsequent pneumatic amplifier is used to control the attached pneumatic actuator.

The SIL Safety Function is intended to open or close actuator/valves assemblies as emergency application.

By providing 0 mA as control/setpoint signal the positioner depressurizes the fail-safe actuator which return spring moves the valve

to a predefined, safe end position (either OPEN or CLOSED).

Figure 1 is demonstrating the safety instrumented function as example on a Tank Overfill Protection.

The TZIDC pneumatic system can be supplied in four versions: for single acting or double acting actuators and each with the ‘fail

safe’ or ‘fail-freeze’ safety behavior.

The SIL Safety Function is limited to the version: ‘single-acting, fail safe‘ in conjunction with pneumatic fail-safe actuators with

spring-return mechanism.