Rockwell Automation Trusted T8424 User manual

ICSTT-RM290F-EN-P (PD-T8824) Trusted
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7
Trusted 40 Channel 120 Vac Digital Input FTA
Product Overview
The Trusted® 40 Channel 120 Vac Digital Input Field Termination Assembly (FTA) T8824 is designed
to act as the main interface between a field device generating a digital signal and the Trusted TMR
120 Vac Digital Input Module T8424.
Features:
•40 input channels per FTA.
•Industry standard field device connections (2-wire).
•Standard DIN rail compatibility.
•Simple installation and connection.
•120 Vac operation.
•Fused field power supply per channel.

Trusted ICSTT-RM290F-EN-P
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7
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Trusted 40 Channel 120 Vac Digital Input FTA PREFACE
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 i
PREFACE
In no event will Rockwell Automation be responsible or liable for indirect or consequential damages
resulting from the use or application of this equipment. The examples given in this manual are
included solely for illustrative purposes. Because of the many variables and requirements related to
any particular installation, Rockwell Automation does not assume responsibility or reliability for
actual use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, with respect to use of information, circuits,
equipment, or software described in this manual.
Allen-Bradley, LISTEN. THINK. SOLVE., Rockwell Automation, TechConnect, and Trusted are
trademarks of Rockwell Automation, Inc.
All trademarks are acknowledged.
DISCLAIMER
It is not intended that the information in this publication covers every possible detail about the
construction, operation, or maintenance of a control system installation. You should also refer to
your own local (or supplied) system safety manual, installation and operator/maintenance manuals.
REVISION AND UPDATING POLICY
This document is based on information available at the time of its publication. The document
contents are subject to change from time to time. The latest versions of the manuals are available at
the Rockwell Automation Literature Library under "Product Information" information "Critical
Process Control & Safety Systems".
TRUSTED RELEASE
This technical manual was updated for Trusted Release 4.0.
LATEST PRODUCT INFORMATION
For the latest information about this product review the Product Notifications and Technical Notes
issued by technical support. Product Notifications and product support are available at the Rockwell
Automation Support Centre at
http://rockwellautomation.custhelp.com
At the Search Knowledgebase tab select the option "By Product" then scroll down and select the
Trusted product.
Some of the Answer ID’s in the Knowledge Base require a TechConnect℠Support Contract. For more
information about TechConnect Support Contract Access Level and Features, click on the following
link:
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/50871
This will get you to the login page where you must enter your login details.

PREFACE Trusted 40 Channel 120 Vac Digital Input FTA
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IMPORTANT A login is required to access the link. If you do not have an account then you can create one
using the "Sign Up" link at the top right of the web page.
DOCUMENTATION FEEDBACK
Your comments help us to write better user documentation. If you discover an error, or have a
suggestion on how to make this publication better, send your comment to our technical support
group at http://rockwellautomation.custhelp.com

Trusted 40 Channel 120 Vac Digital Input FTA PREFACE
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 iii
SCOPE
This manual specifies the maintenance requirements and describes the procedures to assist
troubleshooting and maintenance of a Trusted system.
WHO SHOULD USE THIS MANUAL
This manual is for plant maintenance personnel who are experienced in the operation and
maintenance of electronic equipment and are trained to work with safety systems.
SYMBOLS
In this manual we will use these notices to tell you about safety considerations.
SHOCK HAZARD: Identifies an electrical shock hazard. If a warning label is fitted, it
can be on or inside the equipment.
WARNING: Identifies information about practices or circumstances that can cause
an explosion in a hazardous environment, which can cause injury or death,
property damage or economic loss.
ATTENTION: Identifies information about practices or circumstances that can cause
injury or death.
CAUTION: Identifies information about practices or circumstances that can cause
property damage or economic loss.
BURN HAZARD: Identifies where a surface can reach dangerous temperatures. If a
warning label is fitted, it can be on or inside the equipment.
This symbol identifies items which must be thought about and put in place when
designing and assembling a Trusted controller for use in a Safety Instrumented
Function (SIF). It appears extensively in the Trusted Safety Manual.
IMPORTANT Identifies information that is critical for successful application and understanding of
the product.
NOTE Provides key information about the product or service.
TIP Tips give helpful information about using or setting up the equipment.

PREFACE Trusted 40 Channel 120 Vac Digital Input FTA
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WARNINGS AND CAUTIONS
WARNING: EXPLOSION RISK
Do not connect or disconnect equipment while the circuit is live or unless the area is
known to be free of ignitable concentrations or equivalent
AVERTISSEMENT - RISQUE D’EXPLOSION
Ne pas connecter ou déconnecter l’équipement alors qu’il est sous tension, sauf si
l’environnement est exempt de concentrations inflammables ou équivalente
MAINTENANCE
Maintenance must be carried out only by qualified personnel. Failure to follow these
instructions may result in personal injury.
CAUTION: RADIO FREQUENCY INTERFERENCE
Most electronic equipment is influenced by Radio Frequency Interference. Caution
should be exercised with regard to the use of portable communications equipment
around such equipment. Signs should be posted in the vicinity of the equipment
cautioning against the use of portable communications equipment.
CAUTION:
The module PCBs contains static sensitive components. Static handling precautions
must be observed. DO NOT touch exposed connector pins or attempt to dismantle a
module.

Trusted 40 Channel 120 Vac Digital Input FTA PREFACE
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 v
ISSUE RECORD
Issue Date Comments
5 Jun 16 Rebranded and updated to incorporate IEEE standards with correction of
typographical errors and also standardise the Relative Humidity Range
and Operating Temperature statements in the Specification Section.
6 Aug 17 Figure 2 “Single Channel Schematic” and Voltage details in Specifications
table updated. Clarified distinction between operating range and
measurement range.
7 Jan 19 Spec table and diagrams updated
Updated to display Rockwell Automation publication numbers.
Added trademarks statement.

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Trusted 40 Channel 120 Vac Digital Input FTA Table of Contents
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 1
Table of Contents
1. Description ............................................................................................................ 3
2. Installation............................................................................................................5
3. Associated Cable Selection......................................................................................7
4. Cable Capacitance .................................................................................................. 9
5. Assembly PinoutConnections ............................................................................... 11
5.1. AC Supply TB1 Connections ..................................................................................................... 11
5.2. Field TB2 – TB5 Connections.................................................................................................... 11
5.3. Field TB6 – TB9 Connections.................................................................................................... 12
5.4. Field TB10 – TB13 Connections................................................................................................ 13
5.5. Field TB14 – TB17 Connections................................................................................................ 13
5.6. Field TB18 – TB21 Connections................................................................................................ 14
5.7. SK1 Connections....................................................................................................................... 14
5.8. SK2 Connections....................................................................................................................... 15
5.9. SK3 Connections....................................................................................................................... 15
5.10. SK4 Connections....................................................................................................................... 16
5.11. SK5 Connections....................................................................................................................... 16
6. Specifications....................................................................................................... 19

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Trusted 40 Channel 120 Vac Digital Input FTA 1. Description
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 3
1. Description
Figure 1 T8824 Photo
The Trusted 40 Channel 120 Vac Digital Input FTA T8824 provides termination for a
maximum of 40 input channels from various types of field devices which generate a digital
input. Figure 2 below shows the configuration of a single channel.
Figure 2 Single Channel Schematic
The supply for the field is derived from a 120 Vac feed which is connected to AC Input
terminal block TB1. The supply is then fed to each channel.

1. Description Trusted 40 Channel 120 Vac Digital Input FTA
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The supply voltage to the field is fed via the 50 mA fuse. This effectively limits the current in
the field loop. The incoming signal (digital) from the field device is fed to the digital input
module via a resistive divider. This divides the voltage down to levels suitable for an
analogue measurement.
Revision E T8824 FTAs use two power resistors in series, as shown in the circuit diagram in
Figure 2. Earlier revisions used 4x4 resistor arrays. The resistor arrays on the top half are 68
K and the bottom resistor arrays are 1 K.
Line monitoring is limited to voltage detection on the module. Refer to Trusted TMR 120 Vac
Digital Input Module 40 Channel, publication ICSTT-RM450 (PD-T8424) for details.
The cable linking the 40 channels on the input module to the FTA is terminated at five 10-
way connectors (SK1 to SK5). The input signals from the field (40-off) are connected by 2-
wire arrangements terminated on 5-off 16-way terminal blocks.

Trusted 40 Channel 120 Vac Digital Input FTA 2. Installation
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 5
2. Installation
Trusted 40 Channel 120 Vac Digital Input FTA T8824 is designed to be mounted on either of
the TS32 or TS35 DIN rails in the horizontal or vertical positions as required.
Figure 3 T8824 General Arrangement

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Trusted 40 Channel 120 Vac Digital Input FTA 3. Associated Cable Selection
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 7
3. Associated Cable Selection
Refer to the product descriptions detailed below:
ICSTT-RM311 (PD-TC200) Trusted I/O Companion Slot Cables

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Trusted 40 Channel 120 Vac Digital Input FTA 4. Cable Capacitance
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 9
4. Cable Capacitance
With long field cables the capacitive coupling of the cable can cause a significant voltage to
be seen at the T8424 input when the field switch is open. This causes the T8424 to report
that the field switch is still on when it is turned off.
Revision E T8824 FTAs have lower loop resistance, which reduces the capacitive noise and
increases the available loop length.
The table below shows some estimated maximum lengths for different cables and mains
supplies. Practical distances will be less than this due to other noise and for switching safety
margins.
Revision E Earlier revisions
15 pF/m, 110 V, 50 Hz 2940 m 890 m
30 pF/m, 110 V, 50 Hz 1470 m 470 m
15 pF/m, 110 V, 60 Hz 2450 m 790 m
30 pF/m, 110 V, 60 Hz 1220 m 390 m
15 pF/m, 120 V, 50 Hz 2620 m 850 m
30 pF/m, 120 V, 50 Hz 1310 m 420 m
15 pF/m, 120 V, 60 Hz 2190 m 700 m
30 pF/m, 120 V, 60 Hz 1090 m 350 m
Table 1 Theoretical maximum cable lengths

4. Cable Capacitance Trusted 40 Channel 120 Vac Digital Input FTA
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Trusted 40 Channel 120 Vac Digital Input FTA 5. Assembly Pinout Connections
Rockwell Automation Publication ICSTT-RM290F-EN-P Issue 7 11
5. Assembly Pinout Connections
5.1. AC Supply TB1 Connections
Pin Service
1 120 Vac Live
2 120 Vac Live
3 120 Vac Neutral
4 120 Vac Neutral
Table 2 AC Supply TB1 Connections
Figure 4 AC Supply TB1 Connections
5.2. Field TB2 – TB5 Connections
Pin Loop Power terminal Signal terminal
TB2
1 Channel 1 Channel 1
2 Channel 2 Channel 2
TB3
1 Channel 3 Channel 3
2 Channel 4 Channel 4
TB4 1 Channel 5 Channel 5
TB1
4
1
L L N N

5. Assembly Pinout Connections Trusted 40 Channel 120 Vac Digital Input FTA
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Pin Loop Power terminal Signal terminal
2 Channel 6 Channel 6
TB5
1 Channel 7 Channel 7
2 Channel 8 Channel 8
Table 3 Field TB2 – TB5 Connections
Figure 5 Field TB2 – TB5 Connections
5.3. Field TB6 – TB9 Connections
Pin Loop Power terminal Signal terminal
TB6
1 Channel 9 Channel 9
2 Channel 10 Channel 10
TB7
1 Channel 11 Channel 11
2 Channel 12 Channel 12
TB8
1 Channel 13 Channel 13
2 Channel 14 Channel 14
TB9
1 Channel 15 Channel 15
2 Channel 16 Channel 16
Table 4 Field TB6 – TB9 Connections