Rockwell Automation T7444 User Manual

ICS Regent+Plus

®

PD-7016

AC Digital Output Module

110 VAC

(T7444)

Issue 1,

The AC digital output module provides control of 16 user
output loads. One type of module is available to interface to
outputs powered from a nominal 110 VAC field power su
Each module's triplicated I/O Safetybus interface ensures that
no Regent system failure can incorrectly apply power to an
output, and that no failure in the module can affect the
operation of the Regent system or other I/O modules in the
system.

March, 06

pply.

Features

·

Sixteen output circuits, configured as two isolated groups of
eight circuits each.

·

Hot-replaceable.

·

Automatic self-testing of triplicated I/O Safetybus circuits and
many simplex logic circuits.

·

2 amp output circuits.

·

Zero-cross load switching.

·

Individual front panel indicators on each module show active
and fault, shutdown, blown fuse, and output on/off status (logic
side).

·

2500 volt minimum electrical isolation between field and logic
circuits.

·

Fuses accessible from front panel.

·

TÜV certified, Risk Class 5, non-interfering.

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1

AC Digital Output Module

(T7444)

Module Operation

A block diagram of a typical 110 VAC digital output module is
shown in Figure 1.

The processor modules send triplicated write data commands
to the output module over the I/O Safetybus. The processors’
addressing data and data write commands are voted by the
module (preventing I/O Safetybus failures upstream from the
module from affecting module operation). The voted result is
then passed

to the I/O bus interface logic.

2

Figure 1. Block Diagram of 110 VAC Digital Output Module.

The voted output data from the I/O bus interface logic is then
used to drive the output circuits. Zero crossing turn-on
TRIAC drivers are used to convert the logic level output drive
signals to switch 110 VAC power to load devices.

When the output is logically turned on, the field device is
energized, and when the output is logically turned off, the
field device is de-energized.

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(T7444)

Optical isolation between the module’s logic and field circuits
provides logic-to-field isolation
module from field signal over voltages, transients, and other
electrical disturbances. It also provides a safety barrier
between the primary field voltages and user accessible
circuits.

Each output is individually fused to protect the circuits from
short circuit conditions in output wiring and field devices.

AC Digital Output Module

— protecting the output

Testing and Diagnostics

Each module’s voter circuits are periodical
processor modules. Discrepant data are sent through one of
three legs of the I/O Safetybus to determine whether the
module’s voter is able to outvote the incorrect data. A failure
to return the correct majority-voted result to the processors
produces an I/O module error indication at the processor
modules and a module fault indication at the I/O module.

Each type of module has a unique identification code that is
read by the controller. This code lets the controller know
which type of mo
how to address that module and its points specifically. If a
module is removed, or is replaced with a module of a different
type, the processor modules will indicate an I/O module error.

Loopback logic tests periodically write data to the module and
then read it back to determine whether the module’s I/O bus
interface logic is functioning correctly.

Fuses are continually checked for continuity. Field power
must be connected to the output module for t to detec
fuses. Also, each output must be connected to a minimum
load for a blown fuse to be detected.

dule is installed in each I/O chassis slot and

ly tested by the

t blown

PD-7016

Mar-06

Front Panel

The 110 VAC digital output module is shown in Figure 2. The
front panel contains active and fault status indicators, a
shutdown indicator, and output status and blown fuse
indicators for each output circuit. The front panel also
contains fuses for each output circuit.

3

Note:

AC Digital Output Module

(T7444)

Active and Fault Status Indicators

These green and red LEDs indicate the overall health of the
module. During normal operation, the green ACTIVE
indicator flashes at the controller’s scan rate. If a module
fault is detected the red FAULT indicator turns on and the
green ACTIVE indicator turns off.

Shutdown Indicator

Upon loss of communications with the controller, output
modules enter either a shutdown or hold fault mode. If the I/O
assembly is set to shutdown, the red SHUTDOWN indicator
will turn on when communications with the controller are lost.
If the I/O assembly is set to hold, the SHUTDOWN indi
will always be off (see page 7, Fault Mode Jumper).

cator

When the module is installed in the I/O chassis or when logic

power (from the I/O power supply modules) is first applied to
the module, it will be in the shutdown mode until the first
output scan, regardless of the fault mode jumper settings.
Also, removing two I/O transceiver modules, two I/O power
supply modules, or two power legs will cause the module to be
in the shutdown mode.

Output Status Indicators

The output status indicators are yellow LEDs located on the
logic side of the output. There are 16 output status indicators
— one for each output. These indicators are lit when the
output TRIAC is energized to turn on the load.

Blown Fuse Indicators

The red BLOWN FUSE indicators turn on when the adjacent
front panel fuse opens. A blown fuse will also cause the
module’s FAULT indicator to turn on.

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