(Modules with a K in the last position of the catalog number are
conformally coated to meet noxious gas requirements of ISA/ANSI-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
online at http://literature.rockwellautomation.com
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
available from your local Rockwell Automation sales office or
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 (6562 ft) 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 enclosure must
have suitable flame-retardant properties to prevent or minimize the spread of
flame, complying with a flame spread rating of 5VA, V2, V1, V0 (or equivalent)
if non-metallic. 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.
In addition to this publication, see:
• Industrial Automation Wiring and Grounding Guidelines, for additional
installation requirements, Allen-Bradley publication 1770-4.1
• NEMA Standards publication 250 and IEC publication 60529, as
applicable, for explanations of the degrees of protection provided by
different types of enclosure.
) describes some important differences
.
WARNING
WARNING
ATTENTION
ATTENTION
ATTENTION
ATTENTION
ATTENTION
If 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.
Personnel responsible for the application of safety-related Programmable
Electronic Systems (PES) shall be aware of the safety requirements in the
application of the system and shall be trained in using the system.
Do not remove or replace a Terminal Base unit while power is applied.
Interruption of the backplane can result in unintentional operation or machine
motion.
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 (for example, aluminum or plastic) that can corrode, oxidize,
or are poor conductors, can result in improper or intermittent grounding.
Secure DIN rail to mounting surface approximately every 200 mm (7.8 in.) and
use end-anchors appropriately.
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.
• Use a static-safe workstation, if available.
• Store the equipment in appropriate static-safe packaging when not in
use.
To reduce susceptibility to noise, power analog modules and digital modules
from separate power supplies. Do not exceed a total length of 9.8 ft (3m) for
dc power cabling.
European Hazardous Location Approval
The following frequency input modules are European Zone 2 approved:
1794-IJ2, 1794-IJ2K, and 1794-IJ2XT
European Zone 2 Certification (The following applies when the product bears the Ex
or EEx Marking)
This equipment is intended for use in potentially explosive atmospheres as defined by European
Union Directive 94/9/EC and has been found to comply with the Essential Health and Safety
Requirements relating to the design and construction of Category 3 equipment intended for use
in potentially explosive atmospheres, given in Annex II to this Directive.
Compliance with the Essential Health and Safety Requirements has been assured by compliance
with EN 60079-15 and EN 60079-0.
Publication 1794-IN049D-EN-P - January 2009
2
WARNING
ATTENTION
Observe the following additional Zone 2 certification requirements.
• This equipment is not resistant to sunlight or other sources of UV
radiation.
• This equipment must be installed in an enclosure providing at least IP54
protection when applied in 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
Zone 2 environments.
• Secure any external connections that mate to this equipment by using
screws, sliding latches, threaded connectors, or other means provided
with this product.
• Do not disconnect equipment unless power has been removed or the
area is known to be nonhazardous.
To comply with the CE Low Voltage Directive (LVD), all connections to this
equipment must be powered from a source compliant with the following:
Safety Extra Low Voltage (SELV) or Protected Extra Low Voltage (PELV).
North American Hazardous Location Approval
The following frequency input modules are North American Hazardous
Location approved: 1794-IJ2, 1794-IJ2K, and 1794-IJ2XT.
The following information applies when operating this
equipment in hazardous loca tions:
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
Locations and nonhazardous locations only. Each product is
supplied with markings on the rating nameplate indicating the
hazardous location temperature code. When combining
products within a system, the most adverse temperature code
(lowest “T” number) may be used to help determine the
overall temperature code of the system. Combinations of
equipment in your system are subject to investigation by the
local Authority Having Jurisdiction at the time of installation.
WARNING
EXPLOSION HAZARD
• Do not disconnect equipment
unless power has been removed or
the area is known to be
nonhazardous.
• Do not disconnect connections to
this equipment unless power has
been removed or the area is known
to be nonhazardous. Secure any
external connections that mate to
this equipment by using screws,
sliding latches, threaded
connectors, or other means
provided with this product.
• Substitution of components may
impair suitability for Class I,
Division 2.
• If this product contains batteries,
they must only be changed in an
area known to be nonhazardous.
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
Groupes A, B, C, D dangereux et non dangereux. Chaque produit
est livré avec des marquages sur sa plaque d’identification qui
indiquent le code de température pour les environnements
dangereux. Lorsque plusieurs produits sont combinés dans un
système, le code de température le plus défavorable (code de
température le plus faible) peut être utilisé pour déterminer le
code de température global du système. Les combinaisons
d’équipements dans le système sont sujettes à inspection par
les autorités locales qualifiées au moment de l’installation.
AVERTISSEMENT
RISQUE D’EXPLOSION
• Couper le courant ou s’assurer
que l’environnement est classé
non dangereux avant de
débrancher l'équipement.
• Couper le courant ou s'assurer
que l’environnement est classé
non dangereux avant de
débrancher les connecteurs. Fixer
tous les connecteurs externes
reliés à cet équipement à l'aide
de vis, loquets coulissants,
connecteurs filetés ou autres
moyens fournis avec ce produit.
• La substitution de composants
peut rendre cet équipement
inadapté à une utilisation en
environnement de Classe I,
Division 2.
• S’assurer que l’environnement
est classé non dangereux avant
de changer les piles.
Installing Your Frequency Input Module
7
3
1
2
6
1. Rotate the keyswitch (1) on the terminal base (2) clockwise to
position 1 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 termbase/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.
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-TB3G, and -TB3GS
ATTENTION
ATTENTION
Connect wiring as shown here.
To reduce susceptibility to noise, power analog modules and digital modules
from separate power supplies. Do not exceed a length of 3 m (9.8 ft) for DC
power cabling.
Do not daisy chain power or ground from this terminal base unit to any AC or
DC digital module terminal base units.
Wiring Connections for the Frequency Input Module using the 1794-TB3G
or -TB3GS Terminal Base Unit
Wiring Connections for the 1794-TB3G and -TB3GS
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
3V 6V 24V
16
Chassis
Ground
+V COM
24V dc
Supply In
+24V dc = Terminals C-34 and C-50
COM = C-35 and C-51
Chassis Ground = Terminals B-16, B-33, C-38, C-40 thru 45, and C-47
NC = No connection
For daisy-chaining: Supply in - C-34 (+) and C-35 (-)
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.
5
The module mounts on a 1794-TB3G or -TB3GS terminal base.
Publication 1794-IN049D-EN-P - January 2009
Output Alarm
Connections
Channel 0 Terminals
Sply + Sply
RET
Out + Out
1
RET
Channel 1 Terminals
Sply + Sply
RET
1
Out + Out
RET
SupplyC-37C-39C-46C-48
OutputB-17B-18B-31B-32
1Connect cable shields to GND connections.
3
Types of Inputs
Frequency
24V DC IEC 1+ Proximity
24V DC Contact Switch
500 mV AC Magnetic Pickup A-7A-5A-3A-8A-10A-12
50 mV AC Magnetic Pickup
6V AC VortexA-2A-1A-3A-13A-14A-12
3V AC VortexA-2A-0A-3A-13A-15A-12
Gate
24V DC IEC 1+ Proximity
24V DC Contact Switch
500 mV DC Magnetic Pickup B-24B-22B-20B-25B-27B-29
50 mV DC Magnetic Pickup
1As defined by standard IEC 1131-2.
2RET not used on 2-wire devices.
3Add external resistor from 24V to F (A-6) or G (A-9) for wire-off detection (0.4 mA).
4Add jumper between 50 mV and RET (frequency - channe l 0 = A-4 to A-3; channel 1 = A-11 to
A-12)
(gate - channel 0 = B-21 to B-20; channel 1 = B-28 to B-29).
5Connect cable shields to GND terminals.
6All 4 RET terminals (ch0 and 1, Freq. and Gate) are internally connected together.
Channel 0 Terminals5Channel 1 Terminals
Power Input
1,2
A-7A-6A-3A-8A- 9A-12
3
A-7A-6A-3A-8A- 9A-12
4
A-7A-5A-3A-8A-10A-1 2
1,2
B-24B-23B-20B-25B-26B-29
3
B-24B-23B-20B-25B-26B-29
4
B-24B-22B-20B-25B-27B-29
RET
6
Power Input
5
RET6GND
5
Resolution and Accuracy
+1Hz or +0.1Hz (depending on frequency range bit setting), or + accuracy
specification listed below, whichever is greater.
SSM = Safe state mode
FR = Frequency range
MPM = Missing pulse multiplier
LF = Local Fault mode
F/AAS = Frequency/Accel alarm select
WOFF = Wire-off fault frequency
WOFG = Wire-off fault gate
WOFM = Wire-off fault mode
IGI = Invert gate input
IFI = Invert frequency input
ACT = Acceleration calculation time
MPDM = Missing pulse delay multiplier
R = Reserved
WOF
F Ch
0
WOF
F Ch
1
Ch
0
IGI
Ch
0
IGI
Ch
1
Number of
pulses to
terminate
sampling 0-7
Ch 0
IFI
Minimum Frequency
Ch
Sample Time 0-15
0
Ch 0
IFI
Minimum Frequency
Ch
Sample Time 0-15
1
Ch 1
MPM 0-3
Ch 0
RLFFR
Ch
1
Channel 0
Init
ACT
St
0-3
Up
Ch 0
Ch 0
Channel 1
Init
ACT
St
0-3
Up
Ch 1
Ch 1
Number of
pulses to
terminate
sampling 0-7 Ch
1
F/AA
MPDM
S Ch
0-3 Ch 0
0
F/AA
MPDM
S Ch
0-3 Ch 1
1
F/A
Ch 1
WO
Ch 1
MPA
Ch 1
MPM
0-3
Ch 1
WOFM
0-3 Ch
0
WOFM
0-3 Ch
1
Publication 1794-IN049D-EN-P - January 2009
4
Status Indicators
A
llen
-
B
radley
FREQUENCY
INPUT 2 CHANNEL
FREQGATE
F0F
0
=
Input indicator.
A
B =
Insertable label for writing individual I/O assignments.
C =
Wire-Off Fault indicator.
D =
Output indicator.
E =
Power/status indicator - indicates power applied to module and status of module.
FREQGATE
1F 1F
B
CDA
OUT0OUT
1794-IJ2
1
E
1
OK
1794-IJ2 shown
When an input indicator (yellow) is lighted, it indicates that a valid signal
(active high or active low) is present at one of the Input terminals.
When wire-off detection is enabled, and a wire-off fault is detected (24 V
DC IEC 1+ input terminal only), a fault indicator (red) is blinked/flashed at
a rate of 1Hz to signal a fault condition. A wire-off fault signal will also be
sent to the backplane. A flashing red fault indication means a valid wire-off
condition for a 24 V DC IEC 1+ Input or a 24 V DC contact switch input
with a shunt resistor.
When an output indicator is yellow, the logic is driving an output alarm
On. After detecting a fault, the internal circuitry will set the output data to
the appropriate safe state, as defined by the module data table. Safe state
control may be adapter dependent. The input and output indicators are on
the field side of the isolation path, and display the logic state of the actual
microcontroller input and output.
The status indicator initially powers up as solid green, indicating the power
supply is operating and internal diagnostic tests are being performed. After
a successful power up test, the indicator remains green. The indicator turns
red in about 1.5 s if there is an internal diagnostics error. The module is
operating correctly when the green OK indicator is on.
A red OK indicator shows that the module is in a Faulted condition
(internal error).
IndicatorConditionOperating Description
Input (0, 1)
(Freq, or Gate)
Fault (F)
(Freq, or Gate)
Output Alarm
(0, 1)
Status (OK)Off (Dark)24V Power Turned Off, or 5V Logic Power Problem
Off (Dark)Input Turned Off, Input Not Used, or Wire Disconnected
On (Yellow)Input Turned On (Active High or Active Low if Inverted)
Off (Dark)Wire Connected, Normal Operation or Detection Disabled
On (Red
Flashing)
Off (Dark)Output Alarm Turned Off
On (Yellow)Output Alarm Turned On (Logic Drive On)
Solid GreenModule OK, Normal Operating Mode
Solid RedModule Fault, Outputs Disabled
Wire Disconnected, Fault Condition (for IEC 1+ Proximity switch
or switch contacts with shunt resistor)
Diagnostics
The frequency input module returns diagnostics to the PLC processor in
word 5 of the BTR file. These diagnostics give you information on the
status or condition of the module.
BTR Word 5
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
word 5
See Table for diagnostics
44760
Input
BitDefinition
Word
Word 5 Bits
00 - 03
Specifications - Frequency Input Module, Cat. Nos. 1794-IJ2, 1794-IJ2K, and
1794-IJ2XT
Diagnostic Status - indciates the response from t he module; a normal or
non-normal operating condition.
Bit 03020100
00000 = Normal Operation (No Failure)
00011 = Calibration Failure
00102 = Configuration Failure
A Minimum Frequency Sample Time value other
than 0-9 was selected.
The actual Frequency is greater than 32,767 Hz or
3,276.7 Hz (overange). The scaled Frequency is
greater than 32,767 Hz or 3,27 6.7 Hz (overange).
The % Full Scale calculation (based on Maximum
Frequency) is > 3,276.7%.
Input Specifications
Number of input
channels
Number of inputs per
channel
Input frequencyMaximum - 1-32 kHz w/sine wave; 1-32 kHz w/square wave input
Frequency valueMaximum 32,767 or 3,276.7 (dependent on range)
Input pulse width20 μs
Resolution/AccuracyRefer to Resolution/Accuracy table
On-stage voltage, min10V (24V IEC+1 proximity, encoder input or switch inputs)
On-state voltage, nom
(selected by terminal
base connections)
On-state voltage, maxLimited to isolated 24V DC power supply maximum
On-state current
minimum
nominal
maximum
Off-state current, min1.5 mA into 24V DC IEC+ terminal
Off-state voltage, max5.0V DC on 24V DC IEC+1 terminal
Wire-off detection0.4 mA for proximity, encoder or contact switch with 50 kΩ shunt resistor
Frequency input
impedance
Gate input impedance>5 KΩ for 50 mV Extended Magnetic Pickup
Output Specifications (meets IEC 1A 24V DC output specifications)
Number of outputs2 isolated
Output voltage sourceCustomer supplied
Output voltage
minimum
nominal
maximum
Off-state voltage, max31.2V DC
On-state current1 mA per output minimum
Surge current2 A for 50 ms, repeatable every 2 s
Off-state leakageLess than 300 μA at 31.2V DC maximum
2
2 - Frequency and Gate (gate used to establish direction)
50 mV AC, 28V AC peak - Extended Magnetic Pickup
500 mV AC, 28V AC peak - Magnetic Pickup
< 3V - Vortex Flowmeter low range
> 6V - Vortex Flowmeter high range
24V DC IEC+1 proximity or encoder input
24V DC Contact Switch input
2.0 mA
9.0 mA
10.0 mA
>5 KΩ for 50 mV Extended Magnetic Pickup
>5 KΩ for 500 mV Magnetic Pickup
>10 KΩ for 3V Vortex Flowmeter low range
>10 KΩ for 6V Vortex Flowmeter high range
>2.5 KΩ for 24V DC IEC+1 proximity or encoder input
>2.5 KΩ for 24V DC Contact Switch input
>5 KΩ for 500 mV Magnetic Pickup
>2.5 KΩ for 24V DC IEC+1 proximity or encoder input
>2.5 KΩ for 24V DC Contact Switch input
10V DC
24V DC
31.2V DC
1.0 A per channel sourced out of module maximum
Current Limited - All outputs can be on simultaneously without derating
Publication 1794-IN049D-EN-P - January 2009
5
On-state voltage drop0.9V DC at 1 A
Output controlOutputs individually assignable to: Frequency, % Full Scale or Acceleration
Output switching timeTriggered by frequency alarm or acceleration alarm
General
Module locationCat. No. 1794-TB3G and -TB3GS Terminal Base Units
External DC power
Voltage range
Supply voltage
Supply current
Isolated DC power
Voltage range
Supply voltage
Supply current
Peak AC ripple
Dimensions (with
module installed in
base)
Isolation voltage50V (continuous), Basic Insulation Type
Processing time<4 ms
Flexbus current30 mA at 5V DC
Power dissipation4.6W maximum at 31.2V DC
Thermal dissipationMaximum 15.6 BTU/hr at 31.2V DC
Indicators (field side
driven, logic side
indication)
Keyswitch Position1
Wire sizeDetermined by installed terminal base
Wiring category
Wire typeShielded on signal ports
Terminal screw torque Determined by installed terminal base
Enclosure type rating None (open-style)
North American temp
code
IEC temp codeT4
Alarm
Turn on: Less than 0.5 ms
Turn off: Less than 1 ms
(Input for +5V logic and 24V DC/DC converters)
19.2…31.2V DC (includes 5% AC ripple)
24V DC nominal
220 mA @ 19.2V DC; 180 mA @ 24V DC; 140 mA @ 31.2V DC
(Output to sensors and encoders)
21.6…26.4V DC
24V DC nominal
0-60 mA maximum @ 24V DC (4 devices @ 15 mA = 60 mA)
100 mV maximum
94H x 94W x 69D mm (3.7H x 3.7W x 2.7D in.)
Type tested at 1365V AC for 60 s, between field side and system and
individual channels
1 green/red power/status indicator
4 yellow status indicators (Freq 0, 1, Gate 0, 1)
4 red wire-off indicators (Freq 0, 1, Gate 0, 1)
2 yellow status indicators (Out 0, Out 1) - logic side
1
2 - on signal ports
3 - on power ports
T4A
Environmental
Operating temperature IEC 60068-2-1 (Test Ad, Operating Cold),
4 kV contact discharges (1794-IJ2 and 1794-IJ2K)
6 kV contact discharges (1794-IJ2XT)
8 kV air discharges
10V/m with 1 kHz sine-wave 80% AM from 80…2000 MHz
10V/m with 200 Hz 50% Pulse 100% AM at 900 MHz
10V/m with 200 Hz 50% Pulse 100% AM at 1890 MHz
3V/m with 1 kHz sine-wave 80% AM from 2000…2700 MHz
±2 kV at 5 kHz on power ports
±2 kV at 5 kHz on shielded signal ports
Surge transient
immunity
Conducted RF
immunity
IEC 61000-4-5:
±2 kV line-earth(CM) on shielded signal ports
IEC 61000-4-6:
10V rms with 1 kHz sine-wave 80% AM from 150 kHz…80 MHz on shielded
signal ports
Certifications
Certifications
(when product is
2
marked)
c-UL-usUL Listed Industrial Control Equipment, certified for US and Canada. See UL
CSA
(1794-IJ2 and
1794-IJ2K)
CEEuropean Union 2004/108/EC EMC Directive, compliant with:
ExEuropean Union 94/9/EC ATEX Directive, compliant with:
TÜVTÜV Certified for Functional Safety:
1 Use this Conductor Category information for planning conductor routing. Refer to Industrial
Automation Wiring and Grounding Guidelines, publication
2 See the Product Certification link at http://www.ab.com for Declaration of Conformity, Certificates,
and other certification details.
Valu e
File E65584.
UL Listed for Class I, Division 2 Group A,B,C,D Hazardous Locations, certified
for U.S. and Canada. See UL File E194810.
CSA Certified Process Control Equipment. See CSA File LR54689C.
CSA Certified Process Control Equipment for Class I, Division 2 Group A,B,C,D
Hazardous Locations. See CSA File LR69960C.
EN 61326-1; Meas./Control/Lab., Industrial Requirements
EN 61000-6-2; Industrial Immunity
EN 61000-6-4; Industrial Emissions
EN 61131-2; Programmable Controllers (Clause 8, Zone A & B)
AS/NZS CISPR 11; Industrial Emissions
EN 60079-15; Potentially Explosive Atmospheres, Protection "n" (II 3 G Ex nA
IIC T4 X)
EN 60079-0; General Requirements (Zone 2)
up to and including SIL 2
1770-4.1.
Publication 1794-IN049D-EN-P - January 2009
Publication 1794-IN049D-EN-P - January 2009 6 PN-38821