ABB TZIDC Digital positioner

Brief description

The TZIDC is an electronically configurable positioner with

communication capabilities designed for mounting on

pneumatic linear or rotary actuators. It features a small and

compact design, a modular construction, and an excellent

cost-performance ratio.

Fully automatic determination of the control parameters and

adaptation to the positioner allow for considerable time

savings as well as optimum control behavior.

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.

Dosing of the air flow for pressurizing or depressurizing the

actuator is continuously adjusted. As a result, excellent

control results are achieved. When reaching the setpoint, the

3/3-way valve is closed in center position to minimize the air

consumption.

The pneumatic system can be supplied in four versions: for

single acting and double acting actuators and each with the

‘fail-safe’ / ‘fail-freeze’ safety function.

‘Fail-safe’ safety function

If the electric power supply fails, the positioner output 1 is

depressurized and the return spring in the pneumatic

actuator moves the valve to the safe position. In case of a

‘double-acting’ version, output 2 is additionally pressurized.

‘Fail-freeze’ function

If the electric power supply fails, the positioner Output 1

(and Output 2 if applicable) is closed and the pneumatic

actuator blocks the valve in the current position. If the

compressed air supply power fails, the positioner

depressurizes the actuator.

Use

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

line LCD indicator 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 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, HART®5 or HART®7 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 messages (alarms /

faults).

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.