(Modules with a K in the last position of the catalog number are conformally
coated to meet noxious gas requireme nts of ISA / AN SI-71.040 1985 Class
G3 Environment.)
Important User Information
Solid state equipment has operational characteristics differing from those of
electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (Publication SGI-1.1 available from your local Rockwell
Automation sales office or online at http://www.ab.com/manuals/gi) describes some
important differences between solid state equipment and hard-wired electromechanical
devices. Because of this difference, and also because of the wide variety of uses for solid
state equipment, all persons responsible for applying this equipment must satisfy themselves
that each intended application of this equipment is acceptable.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or
consequential damages resulting from the use or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes.
Because of the many variables and requirements associated with any particular installation,
Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the
examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information,
circuits, equipment, or software described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written permission of
Rockwell Automation, Inc. is prohibited.
Throughout this manual we use notes to make you aware of safety considerations.
WARNING
IMPORTANT
ATTENTION
ATTENTION
Identifies information about practices or circumstances that can cause
an explosion in a hazardous environment, which may lead to personal
injury or death, property damage, or economic loss.
Identifies information that is critical for successful application and
understanding of the product.
Identifies information about practices or circumstances that can lead
to personal injury or death, property damage, or economic loss.
Attentions help you:
• identify a hazard
• avoid a hazard
• recognize the consequence
Environment and Enclosure
This equipment is intended for use in a Pollution Degree 2
industrial environment, in overvoltage Category II applications
(as defined in IEC publication 60664-1), at altitudes up to 2000
meters without derating.
This equipment is considered Group 1, Class A industrial
equipment according to IEC/CISPR Publication 11. Without
appropriate precautions, there may be potential difficulties
ensuring electromagnetic compatibility in other environments
due to conducted as well as radiated disturbance.
This equipment is supplied as "open type" equipment. It must be
mounted within an enclosure that is suitably designed for those
specific environmental conditions that will be present and
appropriately designed to prevent personal injury resulting from
accessibility to live parts. The interior of the enclosure must be
accessible only by the use of a tool. Subsequent sections of this
publication may contain additional information regarding specific
enclosure type ratings that are required to comply with certain
product safety certifications.
See NEMA Standards publication 250 and IEC publication
60529, as applicable, for explanations of the degrees of
protection provided by different types of enclosure. Also, see the
appropriate sections in this publication, as well as the
Allen-Bradley publication 1770-4.1 ("Industrial Automation
Wiring and Grounding Guidelines"), for additional installation
requirements pertaining to this equipment.
WARNING
WARNING
ATTENTION
ATTENTION
When you insert or remove the module while backplane power is on,
an electrical arc can occur. This could cause an explosion in
hazardous location installations. Be sure that power is removed or the
area is nonhazardous before proceeding.
If you connect or disconnect wiring while the field side power is on,
an electrical arc can occur. This could cause an explosion in
hazardous location installations. Be sure that power is removed or the
area is nonhazardous before proceeding..
FLEX I/O is grounded through the DIN rail to chassis ground. Use
zinc plated yellow-chromate steel DIN rail to assure proper grounding.
The use of other DIN rail materials (e.g. aluminum, plastic, etc.) that
can corrode, oxidize, or are poor conductors, can result in improper or
intermittent grounding.
Preventing Electrostatic Discharge
This equipment is sensitive to electrostatic discharge, which can cause
internal damage and affect normal operation. Follow these guidelines
when you handle this equipment:
• Touch a grounded object to discharge potential static.
• Wear an approved grounding wriststrap.
• Do not touch connectors or pins on component boards.
• Do not touch circuit components inside the equipment.
• If available, use a static-safe workstation.
North American Hazardous Location Approval
The following input modules are North American Hazardous Location
approved: 1794-IA8, -IA8K, -IA8I and 1794-IA16.
.
The following information applies when operating this
equipment in hazardous locations:
Products marked “CL I, DIV 2, GP A, B, C, D” are suitable for use
in Class I Division 2 Groups A, B, C, D, Hazardous Lo cations and
nonhazardous loc ations only. Each product is supplied with
markings on the rating nameplate indicating the hazardous
location temperature code. When combining products within a
system, the mos t adverse temperatur e code (lowest “T”
number) may be used to help determine the overall temperature
code of the sys tem. Combinations of e quipment in your system
are subject to i nvestigation by the loca l Authority Having
Jurisdiction at the t ime of installation.
WARNING
EXPLOSION HAZARD
• Do not discon nect equipment unless
power has been removed or the area is
known to be n onhazardous.
• Do not disconnect connections to this
equipment un less power has been
removed or the area is known to be
nonhazardous. Secure any external
connections that mate to this
equipment by using scr ews, sliding
latches, thre aded connectors, or other
means provided with this product.
• Substituti on of components ma y
impair suitability f or Class I,
Division 2.
• If this product contains batteries, they
must only be changed in an area known
to be nonhazar dous.
Informations sur l’utilisation de cet équipement en
environnements dangereux :
Les produits marqués "CL I, DIV 2, GP A, B, C, D" ne
conviennent qu’à une utilisation en environnements de Classe I
Division 2 Grou pes A, B, C, D dangere ux et non dangereux.
Chaque produit est livré avec des mar quages sur sa plaque
d’identificati on qui indiquent le code de température pour les
environnemen ts dangereux. Lorsq ue plusieurs produits s ont
combinés dans un syst ème, le code de température le plus
défavorable (c ode de température le p lus faible) peut être
utilisé pour dé terminer le code de tem pérature global du
système. Les c ombinaisons d’équipeme nts dans le système
sont sujettes à inspe ction par les autorités local es qualifiées
au moment de l’ installation.
AVERTISSEMENT
RISQUE D’EXPLOSION
• Couper le cou rant ou s’assurer que
l’environnement est classé non
dangereux avant de débrancher
l'équipement .
• Couper le cou rant ou s'assurer que
l’environnement est classé non
dangereux avant de débrancher les
connecteurs. Fixer tou s les connecteurs
externes reli és à cet équipement à
l'aide de vis , loquets coulissants,
connecteurs filetés ou autres moyens
fournis avec c e produit.
• La substitut ion de composants peut
rendre cet é quipement inadapté à une
utilisation en en vironnement de Classe
I, Division 2.
• S’assurer que l’environnement est
classé non da ngereux avant de change r
les piles.
FLEX I/O is a trademark of Rockwell Automation
DeviceNet is a trademark of ODVA, Inc.Publication 1794-IN102B-EN-P - June 2004
2
European Hazardous Location Approval
The following module is European Zone 2 approved: 1794-IA8K.
European Zone 2 Certification (The following applies when the product bears
the EEx Marking)
This equipment is intended for use in potentially explosive atmospheres as defined by
European Union Directive 94/9/EC.
The LCIE (Laboratoire Central des Industries Electriques) certifies that this
equipment has been found to comply with the Essential Health and Safety
Requirements relating to the design and construction of Categor y 3 equipment
intended for use in potentially explosive atmospheres, given in Annex II to this
Directive. The examination and test results are recorded in confidential report No. 28
682 010.
Compliance with the Essential Health and Safety Requirements has been assured by
compliance with EN 50021.
IMPORTANT
Observe the following additional Zone 2 certification requirements.
• This equipment is not resistant to sunlight or other sources of UV
radiation.
• The secondary of a current transformer shall not be open-circuited
when applied in Class I, Zone 2 environments.
• Equipment of lesser Enclosure Type Rating must be installed in an
enclosure providing at least IP54 protection when applied in Class I,
Zone 2 environments.
• This equipment shall be used within its specified ratings defined by
Allen-Bradley.
• Provision shall be made to prevent the rated voltage from being
exceeded by transient disturbances of more than 40% when
applied in Class I, Zone 2 environments
Installing Your ac Digital Input Module
7
3
4
1
2
6
5
5. Press firmly and evenly to seat the module in the terminal base unit.
The module is seated when the latching mechanism (7) is locked into
the module.
Connecting Wiring for the 1794-IA8 and -IA8K
1. For 1794-TB2, -TB3, or -TB3S - Connect individual input wiring to
even numbered terminals on the 0-15 row (A) as indicated in the table
below .
For 1794-TBN - Connect individual input wiring to numbered
terminals on the 16-33 row (B) as indicated in the table below.
2. For 1794-TB2 - Connect the associated 120V ac power lead (L1) of
the input device to the corresponding odd numbered terminals on the
0-15 row A for each input as indicated in the table below. (The odd
numbered terminals on row A are internally connected to 120V ac
L1.)
For 1794-TB3, or -TB3S - Connect the associated 120V ac power
lead (L1) of the input device to the corresponding odd numbered
terminals on the 34-51 row (C) or to the corresponding terminal on
row (C) for each input as indicated in the table below. (The odd
numbered terminals on row (A) and the terminals of row (C) are
internally connected to 120V ac power L1.)
For 1794-TBN - Connect the associated 120V ac power lead (L1) of
the input device to the corresponding odd numbered terminal on the
34-51 row (C) for each input as indicated in the table below. (The
120V ac power terminals of row (C) are internally connected
together.)
3. Connect 120V ac power (L1) to terminal 34 on the 34-51 row (C).
4. Connect 120V ac common (L2) to terminal 16 on the 16-33 row (B).
5. If daisychaining power to the next terminal base, connect a jumper
from terminal 51 (+120V ac L1) on this base unit to terminal 34 on
the next base unit
6. .If continuing ac common to the next base unit, connect a jumper
from terminal 33 (120V common L2) on this base unit to terminal 16
on the next base unit.
The module mounts on a 1794 terminal base.
ATTENTION
During mounting of all devices, be sure that all debris
(metal chips, wire strands, etc.) is kept from falling
into the module. Debris that falls into the module
could cause damage on power up.
1. Rotate the keyswitch (1) on the terminal base (2) clockwise to position
8 as required for this type of module.
2. Make certain the flexbus connector (3) is pushed all the way to the left to connect with the neighboring terminal base/adapter. You cannot
install the module unless the connector is fully extended.
3. Make sure the pins on the bottom of the module are straight so they
will align properly with the connector in the terminal base.
WARNING
If you remove or insert the module while the backplane
power is on, an electrical arc can occur. This could cause an
explosion in hazardous location installations. Be sure that
power is removed or the area is nonhazardous before
proceeding..
4. Position the module (4) with its alignment bar (5) aligned with the
groove (6) on the terminal base.
Publication 1794-IN102B-EN-P - June 2004
Wiring Connections for the 1794-IA8 and -IA8K
Input
Input 0A-0
Input 1A-2
Input 2A-4
Input 3A-6
Input 4A-8
Input 5A-10
Input 6A-12
Input 7A-14
A = Input terminals (Even numbe red terminals
0 thru 14)
B = Common terminals
C = Power terminals (C-34 and C-51 on - TB2; C-34
thru C-51 on -TB3 and -TB3S)
1 A-1, 3, 5, 7, 9, 11, 13 and 15 on the 1794-TB2, -TB3 and - TB3S are internally connected in the
module to 120V ac L1.
2 C-1, 3, 5, 7, 9, 11, 13 and 15 on the 1794-TBN are internally connected in the module to
120V ac L1.
1794-TB2,-TB3, -TB3S 1794-TBN
Input
Ter mi nal
120V ac
Supply
A-11/C-35
A-31/C-36
A-51/C-37
A-71/C-38
A-91/C-39
A-111/C-40
A-131/C-41
A-151/C-42
Input
Te rm in al
B-0
B-2
B-4
B-6
B-8
B-10
B-12
B-14
B = Even numbered Input terminals
0-14, ac common terminals 16 and 33
C = Power terminals C-34 and C-51, and
odd numbered input terminals 1 thru 1 5
120V ac
Supply
2
C-1
2
C-3
2
C-5
2
C-7
2
C-9
2
C-11
2
C-13
2
C-15
3
Inputs
)
Even Numbered I/O Terminals 0 thru 14
n)
L
L
U
1794-TB2, -TB3 and -TB3S Terminal Base Wiring for 1794-IA8,
IA8K and -IA16
Connect 120V ac L1 power to terminal C-34
Connect 120V ac common L2 to terminal B-16
Use B-33 and C-51 for daisychaining to the next terminal base unit
(Terminals C-35 thru C-50 not available on the 1794-TB2.)
Commons
Voltage
A
B
L2
C
L1
(1794-TB3 shown
1794-TBN Terminal Base Wiring for 1794-IA8, IA8K
and -IA16
L2
16
34
L1
1 = 120V ac - Connect to terminal C-34
2 = 120V ac common - Connect to terminal B-16
se B-33 and C-51 for daisychaining to the next terminal base unit
4
2
0
1
6789101112
3
5
Odd Numbered I/O Terminals 1 thru 15
L2
14
33
15
B
51
C
L1
(1794-TBN show
13
Connecting Wiring for the 1794-IA16
1. For 1794-TB3, or -TB3S - Connect individual input wiring to
numbered terminals on the 0-15 row (A) as indicated in the table
below .
For 1794-TBN - Connect individual input wiring to even numbered
terminals on the 16-33 row (B), and to the odd numbered terminals
on the 34-51 row (C) as indicated in the table below.
2. For 1794-TB3, or -TB3S - Connect the associated 120V ac power
lead (L1) of the input device to the corresponding terminals on the
34-51 row (C) for each input as indicated in the table below. (The
120V power terminals of row (C) are internally connected together.)
For 1794-TBN - An external terminal strip is needed to distribute
120V ac power (L1) to each device.
120V ac L2Common terminals B-16 thru B-33 (B-16 and B-33 for -TBN) are
1
When using the 1794-TBN, an external terminal strip is needed to connect the 120V ac power
connections.
Input Terminal
1794-TB3, -TB3S
Input Terminal
1794-TBN
internally connected together. Connect 120V ac L1 to C-34
internally connected together. Connect 120V ac common L2 to
terminal B-16
Connecting Wiring for the 1794-IA8I
1. For 1794-TB2, -TB3, or -TB3S - Connect individual input wiring to
even numbered terminals on the 0-15 row (A) as indicated in the table
below .
For 1794-TBN - Connect individual input wiring to even numbered
terminals 0-14 on the 16-33 row (B) as indicated in the table below.
2. For 1794-TB2, -TB3, or -TB3S - Connect the associated 120V ac
common (L2) of the isolated supply to the corresponding odd
numbered terminals on the 0-15 row A for each input as indicated in
the table below.
For 1794-TBN - Connect the associated 120V ac common lead (L2)
of the isolated supply to the corresponding odd numbered terminal
1-15 on the 34-51 row (C) as indicated in the table below.
120V ac
Supply (L1)
1
3. Connect 120V ac power (L1)to terminal 34 on the 34-51 row (C).
4. Connect 120V ac common (L2) to terminal 16 on the 16-33 row (B).
IMPORTANT
Individual isolated 120V ac L1 power leads must
be run externally to each of the input devices.
5. If daisychaining power to the next terminal base, connect a jumper
from terminal 51 (+120V ac L1) on this base unit to terminal 34 on
the next base unit.
6. If continuing ac common to the next base unit, connect a jumper
from terminal 33 (120V common L2) on this base unit to terminal 16
on the next base unit.
A = Even numbered terminals 0 thru 14 for cus tomer
connections; corresponding odd numbered 120V ac
common L2 terminals 1 thru 15 f or customer
connections from isolat ed power supply.
120V ac L2
Common
Input
Ter m in al
B = Even numbered term inals 0 thru 14
for customer connections; C = Odd
numbered120V ac common L2
terminals 1 thru 15 for customer
connections from isolat ed power
supply.
120V ac L2
Common
1794-TB2, -TB3, or -TB3S Terminal Base Wiring for the
1794-IA8I
Number of Inputs8, (1 group of 8), nonisolated8 isolated
Module LocationCat. No. 1794-TB2, -TB3, -TB3S and -TBN Terminal Base Units
On-state Voltage65V ac minimum
On-state Current
Off-state Voltage43V ac maximum
Off-state Current2.9mA minimum
Input Impedance10.6K ohms nominal
Nominal Input Current12mA @ 120V ac, 6 0Hz
Isolation VoltageTested at 2150V dc for 1s between
Input Filter TimeRefer to Input F ilter Time ta ble
Flexbus Current30mA @5V dc
Power Dissipation4.5W maximum @ 132V ac
Thermal DissipationMaximum 15.3 BTU/hr @ 132V ac
Specifications - Cat. No. 1794-IA16
Number of Inputs16 (1 group of 16), nonisolated
Module LocationCat. No. 1794-TB3, -TB3S and -TBN Terminal Base Units
On-state Voltage74V ac minimum
On-state Current1
Off-state Voltage20V ac maximum
Off-state Current2.9 mA minimum
Nominal Input Impedance10K ohms
Nominal Input Current12mA @ 120V ac, 60Hz
Isolation VoltageTested at 2150V dc for 1s between u ser and system
Flexbus Current20mA
Power Dissipation6.4W maximum @ 132V ac
Thermal DissipationMax imum 21.8 BTU/hr @ 132V ac
120V ac nominal
132V ac maximum
1
7.1mA minimum
user and system
No isolation between individual
channels
120V ac nominal
132V ac maximum
minimum
nominal
maximum
5.49mA @ 74V ac, 47Hz
12.06mA @ 120V ac, 60Hz
14.81mA @ 132V ac, 63Hz
No isolation between individual chann els
Tested at 2150V dc for 1s between
user and system and between
individual channels
5
General Specifications
Input Filter Time
Terminal Base Screw
Torque
Dimensions (with module
installed)
Indicators (field side
indication, custome r
device driven)
External ac power
Supply voltage
Voltage range
Keyswitch Position8
Environmental Conditions
Enclosure Type RatingNone (open-style)
Conductors Wire Size
Certifications (when
product is marked)
1 Ac inputs compatible with proximity switches wit h leakage ratings of I
2 Input off-to-on filte r time is the time from a v alid input signal to recogn ition by the module. Input o n-to-off filter
3 You use this category information for planning conductor routing as described in Allen-Bradley
4 For the latest up-to- date information, see the Product Certificat ion link at www.ab.com for Declarations of
2
Off to On
On to Off
Operating
Temperature
Storage Temperature IEC 60068-2-1 (Test Ab, Un-packaged Non-oper ating Cold),