Omron CJ1W-CT021 Installation manual

Machine Automation Controller
CJ-series
High-speed Counter Units
High-speed Counter Units
Operation Manual
for NJ-series CPU Unit
W492-E1-03
CJ1W-CT021

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or
by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission of
OMRON.
No patent liability is assumed with respect to the use of the information contained herein. Moreover, because OMRON is
constantly striving to improve its high-quality products, the information contained in this manual is subject to change without
notice. Every precaution has been taken in the preparation of this manual. Nevertheless, OMRON assumes no responsibility
for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained in
this publication.
OMRON, 2011

1
Introduction
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Introduction
Thank you for purchasing a CJ-series CJ1W-CT021 High-speed Counter Unit.
This manual contains information that is necessary to use the CJ-series CJ1W-CT021 High-speed
Counter Unit for an NJ-series CPU Unit. Please read this manual and make sure you understand the
functionality and performance of the NJ-series CPU Unit before you attempt to use it in a control sys-
tem.
Keep this manual in a safe place where it will be available for reference during operation.
This manual is intended for the following personnel, who must also have knowledge of electrical sys-
tems (an electrical engineer or the equivalent).
•Personnel in charge of introducing FA systems.
•Personnel in charge of designing FA systems.
•Personnel in charge of installing and maintaining FA systems.
•Personnel in charge of managing FA systems and facilities.
For programming, this manual is intended for personnel who understand the programming language
specifications in international standard IEC 61131-3 or Japanese standard JIS B3503.
This manual covers the following products.
•CJ-series CJ1W-CT021 High-speed Counter Unit
Intended Audience
Applicable Products

Relevant Manuals
2CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Relevant Manuals
There are three manuals that provide basic information on the NJ-series CPU Units: the NJ-series CPU
Unit Hardware User’s Manual, the NJ-series CPU Unit Software User’s Manual, and the NJ-series
Instructions Reference Manual.
Most operations are performed from the Sysmac Studio Automation Software. Refer to the Sysmac
Studio Version 1 Operation Manual (Cat. No. W504) for information on the Sysmac Studio.
Other manuals are necessary for specific system configurations and applications.
Read all of the manuals that are relevant to your system configuration and application to make the most
of the NJ-series CPU Unit.
NJ-series User’s Manuals
Basic information
Introduction to NJ-series Controllers
Setting devices and hardware
Using motion control
Using EtherCAT
Using EtherNet/IP
Using CJ-series Units
Software settings
Using motion control
Using EtherCAT
Using EtherNet/IP
Programming
Using motion control
Using EtherCAT
Using CJ-series Units
Programming error processing
Testing operation and debugging
Using motion control
Using EtherCAT
Using EtherNet/IP
Maintenance
Using EtherCAT
Using EtherNet/IP
Using CJ-series Units
NJ-series CPU Unit Hardware User´s Manual NJ-series CPU Unit Software User´s Manual NJ-series Instructions Reference Manual NJ-series CPU Unit Motion Control User´s Manual NJ-series CPU Unit Built-in EtherCAT Port User´s Manual NJ-series Motion Control Instructions Reference Manual NJ-series CPU Unit Built-in EtherNet/IP Port User´s Manual NJ-series Troubleshooting Manual CJ-series Special Unit Operation Manuals for NJ-series CPU Unit
Troubleshooting and managing
errors in an NJ-series Controller
Use the
relevant
manuals for
references
according to
any error that
occurs.

3
Manual Configuration
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Manual Configuration
NJ-series CPU Unit Hardware User’s Manual (Cat. No. W500)
Section Description
Section 1
Introduction This section provides an introduction to the NJ-series Controllers and their features, and gives the NJ-series Controller specifications.
Section 2
System Configuration This section describes the system configuration used for NJ-series Controllers.
Section 3
Configuration Units This section describes the parts and functions of the configuration devices in the NJ- series Controller configuration, including the CPU Unit and Configuration Units.
Section 4
Installation and Wiring This section describes where and how to install the CPU Unit and ConfigurationUnits and how to wire them.
Section 5
Troubleshooting This section describes the event codes, error confirmation methods, and corrections for errors that can occur.
Section 6
Inspection and Maintenance
This section describes the contents of periodic inspections, the service life of the Bat-
tery and Power Supply Units, and replacement methods for the Battery and Power
Supply Units.
Appendices The appendices provide the specifications of the Basic I/O Units, Unit dimensions, load short-circuit protection detection, line disconnection detection, and measures for
EMC Directives.
NJ-series CPU Unit Software User’s Manual (Cat. No. W501)
Section Description
Section 1
Introduction This section provides an introduction to the NJ-series Controllers and their features, and gives the NJ-series Controller specifications.
Section 2
CPU Unit Operation
This section provides information that is necessary to use the CPU Unit, including
how the CPU Unit works and the operations that it performs depending on the status
of the CPU Unit.
Section 3
I/O Ports, Slave Configuration, and
Unit Configuration
This section describes how to use I/O ports, how to create the slave configuration
and unit configuration and how to assign functions.
Section 4
Controller Setup This section describes the initial settings of the function modules.
Section 5
Designing Tasks This section describes the task system and types of tasks.
Section 6
Programming This section describes programming, including the programming languages and the variables and instructions that are used in programming.
Section 7
Checking Operation and Actual
Operation
This section describes the items and procedures for checking the operation of an NJ-
series Controller, including offline debugging procedures.
Section 8
CPU Unit Functions This section describes the functionality provided by the CPU Unit.
Section 9
Communications Setup This section describes how to go online with the CPU Unit and how to connect to other devices.
Section 10
Example of Actual Application Pro-
cedures
This section describes the procedures that are used to actually operate an NJ-series
Controller.
Section 11
Troubleshooting This section describes the event codes, error confirmation methods, and corrections for errors that can occur.
Appendices The appendices provide the CPU Unit specifications, task execution times, specifica- tions of individual system-defined variables, data attribute lists, CJ-series Unit mem-
ory information, CJ-series Unit memory allocation methods, and version information.

Manual Configuration
4CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Sysmac Studio Version 1 Operation Manual (Cat. No. W504)
Section Description
Section 1
Introduction This section provides an overview and lists the specifications of the Sysmac Studio and describes its features and components.
Section 2
Installation and Uninstallation This section describes how to install and uninstall the Sysmac Studio.
Section 3
System Design This section describes the basic concepts for designing an NJ-series System with the Sysmac Studio and the basic operating procedures.
Section 4
Programming This section describes how to create programs with the Sysmac Studio.
Section 5
Online Connections to a Controller This section describes how to go online with a Controller.
Section 6
Debugging This section describes how to debug the programs online on the Controller or debug it offline with the Simulator.
Section 7
Other Functions This section describes other functions that are supported by the Sysmac Studio, including security functions and troubleshooting functions.
Section 8
Reusing Programming This section describes how to reuse the programs that you create with the Sysmac Studio.
Section 9
Support Software Provided with the
Sysmac Studio
This section describes the Support Software that is provided with the Sysmac Studio.
Section 10
Troubleshooting This section describes the error messages that are displayed when you check a pro- gram on the Sysmac Studio and how to correct those errors.
Appendices
The appendices describe the following:
Driver Installation for Direct USB Cable Connection
Specifying One of Multiple Ethernet Interface Cards
Online Help
Simulation Instructions
CJ-series High-speed Counter Units Operation Manual for NJ-series
CPU Unit (Cat. No. W492) (This Manual)
Section Description
Section 1
Introduction This section describes the functionality and the specifications of the High-speed Counter Unit, and the operating procedure.
Section 2
Components, Installation and Wir-
ing
This section describes the details of the components and where and how to install
and wire the High-speed Counter Unit.
Section 3
Operation and Configuration This section describes the functionality of the High-speed Counter Unit and how to configure the Unit.
Section 4
Exchanging Data with CPU This section describes the data exchange between the CPU Unit and High-speed Counter Unit and the definitions of the device variables for CJ-series Unit.
Section 5
Error Processing, Maintenance and
Inspection
This section describes the troubleshooting procedure, event logs and maintenance
procedure for the High-speed Counter Unit.
Section 6
Application Examples This section provides an application example of the High-speed Counter Unit using a sample program.
Appendices ---

5
Manual Configuration
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
CJ-series High-speed Counter Units Operation Manual (Cat. No.
W401)
Section Description
Section 1
Introduction This section describes the functionality and the specifications of the High-speed Counter Unit, and the operating procedure.
Section 2
Components, Installation and Wir-
ing
This section describes the details of the components and where and how to install
and wire the High-speed Counter Unit.
Section 3
Operation and Configuration This section describes the functionality of the High-speed Counter Unit and how to configure the Unit.
Section 4
Exchanging Data with CPU This section describes the data exchange between the CPU Unit and High-speed Counter Unit and data definitions.
Section 5
Error Processing, Maintenance and
Inspection
This section describes the troubleshooting and maintenance procedures for the High-
speed Counter Unit.
Section 6
Application Examples This section provides application examples of the High-speed Counter Unit using pro- gram samples.
Appendices ---

Manual Structure
6CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Manual Structure
The following page structure is used in this manual.
Special information in this manual is classified as follows:
Note References are provided to more detailed or related information.
Page Structure
Special Information
Precautions for Safe Use
Precautions on what to do and what not to do to ensure safe usage of the product.
Precautions for Correct Use
Precautions on what to do and what not to do to ensure proper operation and performance.
Additional Information
Additional information to read as required.
This information is provided to increase understanding or make operation easier.
4-9
4 Installation and Wiring
NJ-series CPU Unit Hardware User’s Manual (W500)
stinUgnitnuoM3-4
4
stnenopmoCrellortnoCgnitcennoC1-3-4
4-3 Mounting Units
The Units that make up an NJ-series Controller can be connected simply by pressing theUnits together
and locking the sliders by moving them toward the back of the Units. The End Cover is connectedin the
same way to the Unit on the far right side of the Controller.
1Join the Units so that the connectors fit exactly.
2The yellow sliders at the top and bottom of each Unit lock the Units together. Move the sliders
toward the back of the Units as shown below until they click into place.
Precautions for Correct UsePrecautions for Correct Use
The sliders on the tops and bottoms of the Power Supply Unit, CPU Unit, I/O Units, Special I/O
Units, and CPU Bus Units must becompletely locked (until they click into place) after connecting
the adjacent Unit connectors.
4-3-1 Connecting Controller Components
Connector
Hook Hook holes
Slider
Lock
Release
Move the sliders toward the back
until they lock into place.
Level 1 heading
Level 2 heading
Level 3 heading
Level 2 heading
A step in a procedure
Manual name
Special information
Level 3 heading
Page tab
Gives the current
headings.
Indicates a procedure.
Icons indicate
precautions, additional
information, or reference
information.
Gives the number
of the main section.
This illustration is provided only as a sample. It may not literally appear in this manual.

7
Manual Structure
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
In this manual, “download” refers to transferring data from the Sysmac Studio to the physical Controller
and “upload” refers to transferring data from the physical Controller to the Sysmac Studio.
For the Sysmac Studio, synchronization is used to both upload and download data. Here, “synchronize”
means to automatically compare the data for the Sysmac Studio on the computer with the data in the
physical Controller and transfer the data in the direction that is specified by the user.
Precaution on Terminology

Manual Structure
8CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)

9
Sections in this Manual
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Sections in this Manual
6
5
Introduction
Components, Installation and Wiring
Operation and Configuration
Exchanging Data with CPU
Error Processing, Maintenance and Inspection
Application Examples
Appendices
A
4
3
2
1
1
2
3
4
5
6
A
Index
I
I

10 CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
CONTENTS
CONTENTS
Introduction ...............................................................................................................1
Relevant Manuals......................................................................................................2
Manual Configuration ...............................................................................................3
Manual Structure.......................................................................................................6
Sections in this Manual ............................................................................................9
CONTENTS...............................................................................................................10
Read and Understand this Manual ........................................................................13
Safety Precautions..................................................................................................16
Precautions for Safe Use........................................................................................21
Precautions for Correct Use...................................................................................27
Regulations and Standards....................................................................................30
Unit Versions ...........................................................................................................32
Related Manuals......................................................................................................34
Revision History......................................................................................................35
Section 1 Introduction
1-1 Features and Functions..........................................................................................................1-2
1-2 Basic Configuration ................................................................................................................1-5
1-3 Specifications and Characteristics........................................................................................ 1-7
1-3-1 General Specifications................................................................................................................1-7
1-3-2 Functional Specifications ............................................................................................................1-8
1-3-3 Input Specifications...................................................................................................................1-10
1-3-4 Output Specifications................................................................................................................1-12
1-4 Quick Start Up Reference Guide.......................................................................................... 1-14
1-4-1 Configuring the High-speed Counter Unit.................................................................................1-17
1-5 Operating Procedure Guidelines.......................................................................................... 1-19
1-6 Application Areas.................................................................................................................. 1-22
Section 2 Components, Installation and Wiring
2-1 Components and Switch Settings..........................................................................................2-2
2-1-1 Components................................................................................................................................2-2
2-1-2 Indicators.....................................................................................................................................2-3
2-1-3 Counter Type Switch...................................................................................................................2-4
2-1-4 Machine Number Switch.............................................................................................................2-5

11
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
CONTENTS
2-2 Installation................................................................................................................................ 2-6
2-2-1 System Configuration Precautions ............................................................................................. 2-6
2-2-2 Installing Units ............................................................................................................................ 2-6
2-3 Wiring ....................................................................................................................................... 2-8
2-3-1 Connector Pin-layout .................................................................................................................. 2-8
2-3-2 Connector Wiring Methods......................................................................................................... 2-9
2-3-3 Important Wiring Considerations.............................................................................................. 2-13
2-3-4 Internal Circuitry ....................................................................................................................... 2-13
2-3-5 Digital I/O Circuit Configurations............................................................................................... 2-15
2-3-6 Counter Input Configurations.................................................................................................... 2-17
Section 3 Operation and Configuration
3-1 Overview................................................................................................................................... 3-2
3-1-1 Summary.................................................................................................................................... 3-2
3-1-2 List of Functions/Allocation Areas by Purpose ........................................................................... 3-2
3-2 Counter Types.......................................................................................................................... 3-6
3-2-1 Simple Counter........................................................................................................................... 3-7
3-2-2 Circular Counter........................................................................................................................ 3-10
3-2-3 Linear Counter.......................................................................................................................... 3-12
3-3 Input Signal Types................................................................................................................. 3-14
3-3-1 Phase Differential ..................................................................................................................... 3-14
3-3-2 Up & Down Pulse...................................................................................................................... 3-15
3-3-3 Pulse & Direction...................................................................................................................... 3-16
3-4 Digital Input Functions.......................................................................................................... 3-17
3-5 Output Control....................................................................................................................... 3-21
3-5-1 Range Mode............................................................................................................................. 3-23
3-5-2 Comparison Mode .................................................................................................................... 3-29
3-5-3 Manual Output Control.............................................................................................................. 3-36
3-5-4 Output Control Configuration.................................................................................................... 3-37
3-6 Reset Counter........................................................................................................................ 3-38
3-7 Extra Functions ..................................................................................................................... 3-40
3-7-1 Programmable Output Pulses................................................................................................... 3-40
3-7-2 Hysteresis................................................................................................................................. 3-42
3-7-3 Noise Filtering........................................................................................................................... 3-43
3-7-4 Initial Counter Value.................................................................................................................. 3-44
Section 4 Exchanging Data with CPU
4-1 Overview................................................................................................................................... 4-2
4-1-1 Data Flow.................................................................................................................................... 4-2
4-1-2 Unit Restart................................................................................................................................. 4-4
4-1-3 Access from User Program......................................................................................................... 4-5
4-2 Memory Allocation .................................................................................................................. 4-7
4-2-1 Memory Mapping........................................................................................................................ 4-7
4-2-2 Allocating Ranges and Comparison Data................................................................................... 4-7
4-2-3 Details of Device Variables for CJ-series Unit (for input/output)............................................... 4-11
4-2-4 Details of Device Variables for CJ-series Unit (for setting) ....................................................... 4-16
4-2-5 Memory Allocation for Ranges.................................................................................................. 4-23
4-2-6 Memory Allocation for Comparison data .................................................................................. 4-27

12 CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
CONTENTS
Section 5 Error Processing, Maintenance and Inspection
5-1 Error Indicators .......................................................................................................................5-2
5-1-1 Errors during initial processing....................................................................................................5-2
5-1-2 Errors during normal operation...................................................................................................5-3
5-2 Error codes............................................................................................................................... 5-4
5-2-1 DM-configuration errors ..............................................................................................................5-5
5-2-2 Overflow/Underflow errors...........................................................................................................5-6
5-2-3 Preset Error.................................................................................................................................5-7
5-2-4 System Errors .............................................................................................................................5-7
5-3 Event Logs ............................................................................................................................... 5-8
5-3-1 Overview of the Event Logs ........................................................................................................5-8
5-3-2 Error Table...................................................................................................................................5-9
5-3-3 Error Descriptions .....................................................................................................................5-10
5-4 Maintenance and Inspection ................................................................................................ 5-12
5-4-1 Cleaning....................................................................................................................................5-12
5-4-2 Routine Inspections...................................................................................................................5-12
Section 6 Application Examples
6-1 Flow Control............................................................................................................................. 6-2
Appendices
A-1 Differences of NJ Series from CJ Series...............................................................................A-2
A-1-1 Functional Difference..................................................................................................................A-2
A-1-2 Differences in Access Methods from a User Program ................................................................A-4
A-2 Using Terminal Block Units with Screw-terminals .............................................................A-14
A-3 Description of the Response Time.......................................................................................A-16
A-4 Application Restrictions .......................................................................................................A-17
Index

13
Read and Understand this Manual
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Read and Understand this Manual
Please read and understand this manual before using the products. Please consult your OMRON
representative if you have any questions or comments.
Warranty and Limitations of Liability
WARRANTY
OMRON's exclusive warranty is that the products are free from defects in materials and workmanship for a
period of one year (or other period if specified) from date of sale by OMRON.
OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, REGARDING NON-
INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR PARTICULAR PURPOSE OF THE
PRODUCTS. ANY BUYER OR USER ACKNOWLEDGES THAT THE BUYER OR USER ALONE HAS
DETERMINED THAT THE PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR
INTENDED USE. OMRON DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED.
LIMITATIONS OF LIABILITY
OMRON SHALL NOT BE RESPONSIBLE FOR SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES,
LOSS OF PROFITS OR COMMERCIAL LOSS IN ANY WAY CONNECTED WITH THE PRODUCTS,
WHETHER SUCH CLAIM IS BASED ON CONTRACT, WARRANTY, NEGLIGENCE, OR STRICT
LIABILITY.
In no event shall the responsibility of OMRON for any act exceed the individual price of the product on which
liability is asserted.
IN NO EVENT SHALL OMRON BE RESPONSIBLE FOR WARRANTY, REPAIR, OR OTHER CLAIMS
REGARDING THE PRODUCTS UNLESS OMRON'S ANALYSIS CONFIRMS THAT THE PRODUCTS
WERE PROPERLY HANDLED, STORED, INSTALLED, AND MAINTAINED AND NOT SUBJECT TO
CONTAMINATION, ABUSE, MISUSE, OR INAPPROPRIATE MODIFICATION OR REPAIR.

Read and Understand this Manual
14 CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Application Considerations
SUITABILITY FOR USE
OMRON shall not be responsible for conformity with any standards, codes, or regulations that apply to the
combination of products in the customer's application or use of the products.
At the customer's request, OMRON will provide applicable third party certification documents identifying
ratings and limitations of use that apply to the products. This information by itself is not sufficient for a
complete determination of the suitability of the products in combination with the end product, machine,
system, or other application or use.
The following are some examples of applications for which particular attention must be given. This is not
intended to be an exhaustive list of all possible uses of the products, nor is it intended to imply that the uses
listed may be suitable for the products:
• Outdoor use, uses involving potential chemical contamination or electrical interference, or conditions or
uses not described in this manual.
• Nuclear energy control systems, combustion systems, railroad systems, aviation systems, medical
equipment, amusement machines, vehicles, safety equipment, and installations subject to separate
industry or government regulations.
• Systems, machines, and equipment that could present a risk to life or property.
Please know and observe all prohibitions of use applicable to the products.
NEVER USE THE PRODUCTS FOR AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR
PROPERTY WITHOUT ENSURING THAT THE SYSTEM AS A WHOLE HAS BEEN DESIGNED TO
ADDRESS THE RISKS, AND THAT THE OMRON PRODUCTS ARE PROPERLY RATED AND
INSTALLED FOR THE INTENDED USE WITHIN THE OVERALL EQUIPMENT OR SYSTEM.
PROGRAMMABLE PRODUCTS
OMRON shall not be responsible for the user's programming of a programmable product, or any
consequence thereof.

15
Read and Understand this Manual
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Disclaimers
CHANGE IN SPECIFICATIONS
Product specifications and accessories may be changed at any time based on improvements and other
reasons.
It is our practice to change model numbers when published ratings or features are changed, or when
significant construction changes are made. However, some specifications of the products may be changed
without any notice. When in doubt, special model numbers may be assigned to fix or establish key
specifications for your application on your request. Please consult with your OMRON representative at any
time to confirm actual specifications of purchased products.
DIMENSIONS AND WEIGHTS
Dimensions and weights are nominal and are not to be used for manufacturing purposes, even when
tolerances are shown.
PERFORMANCE DATA
Performance data given in this manual is provided as a guide for the user in determining suitability and does
not constitute a warranty. It may represent the result of OMRON's test conditions, and the users must
correlate it to actual application requirements. Actual performance is subject to the OMRON Warranty and
Limitations of Liability.
ERRORS AND OMISSIONS
The information in this manual has been carefully checked and is believed to be accurate; however, no
responsibility is assumed for clerical, typographical, or proofreading errors, or omissions.

Safety Precautions
16 CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Safety Precautions
The following notation is used in this manual to provide precautions required to ensure safe usage of a
CJ-series High-speed Counter Unit. The safety precautions that are provided are extremely important
to safety. Always read and heed the information provided in all safety precautions.
The following notation is used.
Definition of Precautionary Information
WARNING Indicates a potentially hazardous situation which, if not avoided,
could result in death or serious injury. Additionally, there may be
severe property damage.
Caution Indicates a potentially hazardous situation which, if not avoided,
may result in minor or moderate injury, or property damage.
Precautions for Safe Use
Indicates precautions on what to do and what not to do to ensure safe usage of the product.
Precautions for Correct Use
Indicates precautions on what to do and what not to do to ensure proper operation and performance.

17
Safety Precautions
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Symbols
The circle and slash symbol indicates operations that you must not do.
The specific operation is shown in the circle and explained in text.
This example indicates prohibiting disassembly.
The triangle symbol indicates precautions (including warnings).
The specific operation is shown in the triangle and explained in text.
This example indicates a precaution for electric shock.
The triangle symbol indicates precautions (including warnings).
The specific operation is shown in the triangle and explained in text.
This example indicates a general precaution.
The filled circle symbol indicates operations that you must do.
The specific operation is shown in the circle and explained in text.
This example shows a general precaution for something that you must do.

Safety Precautions
18 CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
WARNING
During Power Supply
Do not touch any of the terminals or terminal blocks while the power is being
supplied. Doing so may result in electric shock.
Do not attempt to take any Unit apart. In particular, high-voltage parts are
present in the Power Supply Unit while power is supplied or immediately
after power is turned OFF. Touching any of these parts may result in electric
shock. There are sharp parts inside the Unit that may cause injury.
Fail-safe Measures
Provide safety measures in external circuits to ensure safety in the system if
an abnormality occurs due to malfunction of the CPU Unit, other Units, or
slaves or due to other external factors affecting operation. Not doing so may
result in serious accidents due to incorrect operation.
Emergency stop circuits, interlock circuits, limit circuits, and similar safety
measures must be provided in external control circuits.
The Controller outputs may remain ON or OFF due to deposition or burning
of the output relays or destruction of the output transistors. As a countermea-
sure for such problems, external safety measures must be provided to
ensure safe operation of the system.
The CPU Unit will turn OFF all outputs from Basic Output Units in the follow-
ing cases. The remote I/O slaves will operate according to the settings in the
slaves.
• If an error occurs in the power supply
• If the power supply connection becomes faulty
• If a CPU watchdog timer error or CPU reset occurs
• If a major fault level Controller error occurs
• While the CPU Unit is on standby until RUN mode is entered after the
power is turned ON
External safety measures must be provided to ensure safe operation of the
system in such cases.
If external power supplies for slaves or other devices are overloaded or
short-circuited, the voltage will drop, outputs will turn OFF, and the system
may be unable to read inputs. Provide external safety measures in controls
with monitoring of external power supply voltage as required so that the sys-
tem operates safely in such a case.