The ABB TZIDC represents the digital, intelligent positioner for communication via HART within the ABB TZIDC positioner family.

Unmatched shock and vibration immunity of 10g up to 80Hz distinguishes the ABB TZIDC from others and guarantees reliable operation in almost all areas under harshest environmental conditions.

Pneumatics
An I/P module with subsequent pneumatic amplifier is used to control the pneumatic actuator. The well-proven I/P module proportionally converts the permanent electrical setpoint signal from the CPU into a pneumatic signal used to adjust a 3/3-way valve.

The air flow for pressurising or depressurising the actuator is continuously adjusted. As a result, excellent control is achieved. When reaching the set-point, the 3/3-way valve is closed in centre position to minimize the air consumption. Four different pneumatics versions are available: for single-acting or double-acting actuators, each with “fail-safe” or “fail-freeze” function.

“Fail-safe” function
If the electrical supply power fails, the positioner output 1 is depressurised, and the pneumatic actuator’s return spring moves the valve to the defined safe position. In case of a double-acting actuator the second output 2 is additionally pressurised.

“Fail-freeze” function
If the electrical supply power fails, the positioner output 1 (and 2, if applicable) is closed and the pneumatic actuator stops (“freezes”) the valve in the current position. If the compressed air supply power fails, the positioner depressurizes the actuator.

Use
The ABB TZIDC positioner has a built-in operating panel providing a 2-line LCD display and 4 operating buttons for commissioning, configuration and monitoring during live operation. Alternatively, the appropriate configuration program can be used via the available communication interface.

Communication
The ABB TZIDC positioner has a local communication interface (LCI) as standard. Additionally, a “HART communication” option for communication via the 20 mA signal is available. Both communications are based on the HART Protocol. Alternatively, HART5 or HART7 are available.

Inputs / Outputs
In addition to its input for the analog position setpoint, the positioner is equipped with a digital input which can be used to activate control system functions in the device. A digital output allows you to output collective alarms or fault messages.

Modular design
The basic model can be enhanced at any time by retrofitting optional equipment. Option modules can be installed for analog and digital position feedback. Additionally, a mechanical position indicator, proximity switches or 24 V microswitches are available for indicating the position independently of the mother board function.