ABB TZIDC Electro-Pneumatic Positioner

ABB TZIDC Electro-Pneumatic Positioner
The TZIDC is an electronicallyconfigurable positioner with

1.1.2“Fail-freeze”function

communication capabilities designed for mounting to pneumatic

linear or rotary actuators. It features a small and compact design, a

If the electrical power supply should fail, the positioner output 1 (and

modular construction, and an excellent cost-performance ratio.

2, if applicable)is closed and the pneumatic actuator stops

Fully automaticdetermination of the control parameters and

("freezes") the valve in the current position. If compressed air supply

adaptation to the final control element yield considerable time savings

should fail, the positioner depressurizes the actuator.

and an optimal control behavior.

1.2 Operation

1.1 Pneumatics

The positioner has a built-in operating panel providing a 2-line LCD

An I/P module with subsequent pneumatic amplifier is used to control

and 4 pushbuttons for optimal local configuration,commissioning and

the pneumatic actuator. The well-proven I/P module proportionally

operational monitoring.

converts the permanent electrical positioning signal from the CPU

Altematively, the appropriate configuration program and the available

into a pneumatic signal used to adjust a 3/3-way valve.

communication option can be used.

The air flow for pressurizing or depressurizing 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 center

1.3 Communication

position to minimize the air consumption.

Four different pneumatics versions are available: for single-acting or

The standard TZIDC model has a local communication interface (LKS

double-acting actuators, each with "fail-safe" or "fail-freeze" function.

connector). Additionally, a “HARTcommunication" option for

communication via the 20mA signal is available. Both

communications are based on the HART Protocol.

1.1.1“Fail-safe”function

If the electricalpower supply fails, the positioner output 1 is

1.4 Inputs and outputs

depressurized, and the pneumatic actuator's return spring moves the

valve to the defined safe position. In case of a double-acting actuator

In addition to its input for the analog position set point the TZIDC

the second output 2 is additionally pressurized.

positioner is equipped with a digital input which can be used to

activate various protective functions in the device via the process

control system. A digital output allows you to output collective alarms

or fault messages.

1.5Modular design

The TZIDC basic model can be enhanced at any time by retrofitting

optional equipment.Option modules for analog or digital position

feedback or a shutdown-module can be installed. Additionally, a

mechanical position indicator, proximity switches or 24V

microswitches are available for indicating the position independently

of the mother board function.