User manual OMRON CJ2 CPU UNIT HARDWARE

[. . . ] CJ2 CPU Unit Hardware USER'S MANUAL OMRON, 2008 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. [. . . ] W370) 5 5-4-5 Electrical Environment CJ2 CPU Unit Hardware User's Manual 5-49 5 Installation 5-4-6 Grounding Grounding has the following two purposes. · Protective Grounding Protective grounding is done to ensure safety. It is intended to prevent electrical shock by grounding the electrical potential that is generated by factors such as leakage, induction, or failure. · Functional Grounding Functional grounding is done to protect device and system functions, including prevention of noise from external sources, or prevention of noise from devices or equipment that could have harmful effects on other devices or equipment. Grounding requirements sometimes depend on the situation, based on experimentation. It is important to sufficiently check the particular circumstances before grounding. Grounding Methods and Precautions Principles of One-point Grounding For devices to operate properly, the reference potential between the devices must be stabilized. Use one-point grounding so that noise current does not flow to ground lines between the devices. Whenever possible, use an independent ground (with the ground pole separated by a minimum of 10 m from any other ground pole). · Ground to 100 or less, and if possible use a separate ground from those of other devices. (Refer to figure (a) in the diagram below. ) · If using an independent ground is not possible, then use a common ground as shown in figure (b). · Never connect to the same ground as a device that draws a large amount of power, such as a motor or inverter. · To prevent electrical shock, do not connect to ground poles (especially steel frames) to which multiple devices are connected. · Use a ground pole as close to the PLC as possible and keep the ground line as short as possible. PLC Other device PLC Other device PLC Other device Ground of 100 or less Independent grounds: Best Common ground: Acceptable Common ground: Incorrect Grounding Methods 5-50 CJ2 CPU Unit Hardware User's Manual 5 Installation Precautions when Grounding · If the same ground is used for both the signal lines and the enclosure, isolate the channel base (a grounded metal plate inside a control panel) with an insulating material CS/CJ-series PLCs have an isolated (floating) mounting structure to make it more difficult to be affected by noise from an installation environment, such as a control panel. Independent ground Insulating material Channel base 5-4 Control Panel Installation Example: Insulating and Grounding an Enclosure · To prevent influence from leakage current from other electrical devices, electrically isolate the panel in which the PLC is housed from other devices. · If high-frequency equipment is present, then ground not only the high-frequency equipment but also the panel itself in which the PLC is housed. · As shown in the following diagram, when using shielded cable for I/O wiring, connect the shield near the PLC to the enclosure ground terminal. Follow the instructions in the Communications Unit manual for preparing shielded communications cable. PLC Input Common Output Common 5 5-4-6 Grounding Shielded Cable Ground PLC Ground Terminals The PLC has the following two ground terminals. Protective ground terminal: Always connected to the PLC chassis to prevent electrical shock. Functional ground terminal: Connected to a neutral point in the noise filter to provide a ground when power supply noise causes malfunctioning. When the functional ground terminal is correctly grounded, it is generally effective in suppressing power supply common noise. Occasionally, however, grounding this terminal will result in picking up more noise, so be careful when using it. AC side PLC side PLC Ground Terminals Grounding for AC Power Supply Units When wiring to an AC Power Supply Unit, if one power supply phase of the equipment is grounded, always connect the grounded phase to the L2/N terminal. L1 L2/N CJ2 CPU Unit Hardware User's Manual 5-51 5 Installation 5-52 CJ2 CPU Unit Hardware User's Manual Troubleshooting This section describes how to troubleshoot problems that may occur with a CJ2 PLC. 6-1 CPU Unit Errors . 6-2 6-2 6-3 6-3 6-5 6-6 6-7 6 6-2 Troubleshooting Built-in EtherNet/IP Port Errors (CJ2H-CPU6@-EIP and CJ2M-CPU3@ Only) . 6-25 6-2-1 6-2-2 6-3-1 Checking Built-in EtherNet/IP Port Error Status . 6-25 Checking Error Status at the EtherNet/IP Port Seven-segment Display . 6-28 CJ2 CPU Unit Hardware User's Manual 6-1 6 Troubleshooting 6-1 6-1-1 CPU Unit Errors Errors and Remedies Use the following procedure when an error occurs. Error occurs. Check the indicators. Check the indicators on the front of the CPU Unit and Power Supply Unit, or use the CX-Programmer to read the error status. Identify the error from the indicators (refer to 6-1-6 Types of Errors) or use the CX-Programmer to read the error status. Take measures to eliminate the error that occurred and to prevent it from occurring again. [. . . ] 7-10 Power Supply Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21 program capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5, 2-6 Pulse I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17, A-101 CJ2 CPU Unit Hardware User's Manual Index-1 R replacement notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10 rotary switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ]