OMRON K7GE-MG User Manual

Overview

Procedure

Insulation Resistance Monitoring Device

User's Manual K7GE-MG

Installation and

Wiring

Functions Related

to Measurement

Using Setting

Parameters

Remote Monitoring

Troubleshooting

Appendices

Index

N224-E1-01

NOTE

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.

Trademarks

• Microsoft, Windows is either registered trademarks or trademarks of Microsoft Corporation in the United States and other countries.

• Megger is a registered trademark or trademark of Megger Group Limited.

• Modbus is a registered trademark or trademark of Schneider Electric USA, Inc. in Japan, the United States or other countries.

Other company names and product names in this document are the trademarks or registered trademarks of their respective companies.

Copyrights

Microsoft product screen shots reprinted with permission from Microsoft Corporation.

Preface

Thank you for purchasing a K7GE-MG Insulation Resistance Monitoring Device. This manual describes how to use the K7GE-MG. Read this manual thoroughly and be sure you understand it before attempting to use the K7GE-MG correctly according to the information provided. Keep this manual in a safe place for easy reference. A PDF version of this manual can be downloaded from the OMRON website. (http://www.omron.com)

In this manual, "K7GE-MG" refers to the K7GE-MG with its Main Unit connected to the Probe Units.

It is assumed that the load that the K7GE-MG measures is a motor. Before you use it for other equipment such as a heater or transformer, carefully study the operating specifications of the K7GE-MG.

Preface

Insulation Resistance Monitoring Device User’s Manual (N224)

Terms and Conditions Agreement

Warranty, Limitations of Liability

Warranties

 Exclusive Warranty

Omron’s exclusive warranty is that the Products will be free from defects in materials and workmanship for a period of twelve months from the date of sale by Omron (or such other period expressed in writing by Omron). Omron disclaims all other warranties, express or implied.

 Limitations

OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, ABOUT NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OF THE PRODUCTS. BUYER ACKNOWLEDGES THAT IT ALONE HAS DETERMINED THAT THE PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR INTENDED USE. Omron further disclaims all warranties and responsibility of any type for claims or expenses based on infringement by the Products or otherwise of any intellectual property right.

 Buyer Remedy

Omron’s sole obligation hereunder shall be, at Omron’s election, to (i) replace (in the form originally shipped with Buyer responsible for labor charges for removal or replacement thereof) the non-complying Product, (ii) repair the non-complying Product, or (iii) repay or credit Buyer an amount equal to the purchase price of the non-complying Product; provided that in no event shall Omron be responsible for warranty, repair, indemnity or any other claims or expenses 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. Return of any Products by Buyer must be approved in writing by Omron before shipment. Omron Companies shall not be liable for the suitability or unsuitability or the results from the use of Products in combination with any electrical or electronic components, circuits, system assemblies or any other materials or substances or environments. Any advice, recommendations or information given orally or in writing, are not to be construed as an amendment or addition to the above warranty.

See http://www.omron.com/global/ or contact your Omron representative for published information.

Limitation on Liability; Etc

OMRON COMPANIES SHALL NOT BE LIABLE FOR SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, LOSS OF PROFITS OR PRODUCTION OR COMMERCIAL LOSS IN ANY WAY CONNECTED WITH THE PRODUCTS, WHETHER SUCH CLAIM IS BASED IN CONTRACT, WARRANTY, NEGLIGENCE OR STRICT LIABILITY. Further, in no event shall liability of Omron Companies exceed the individual price of the Product on which liability is asserted.

Insulation Resistance Monitoring Device User’s Manual (N224)

Application Considerations

Suitability of Use

Omron Companies shall not be responsible for conformity with any standards, codes or regulations which apply to the combination of the Product in the Buyer’s application or use of the Product. At Buyer’s request, Omron will provide applicable third party certification documents identifying ratings and limitations of use which apply to the Product. This information by itself is not sufficient for a complete determination of the suitability of the Product in combination with the end product, machine, system, or other application or use. Buyer shall be solely responsible for determining appropriateness of the particular Product with respect to Buyer’s application, product or system. Buyer shall take application responsibility in all cases. NEVER USE THE PRODUCT FOR AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR PROPERTY OR IN LARGE QUANTITIES WITHOUT ENSURING THAT THE SYSTEM AS A WHOLE HAS BEEN DESIGNED TO ADDRESS THE RISKS, AND THAT THE OMRON PRODUCT(S) IS PROPERLY RATED AND INSTALLED FOR THE INTENDED USE WITHIN THE OVERALL EQUIPMENT OR SYSTEM.

Terms and Conditions Agreement

Programmable Products

Omron Companies shall not be responsible for the user’s programming of a programmable Product, or any consequence thereof.

Disclaimers

Performance Data

Data presented in Omron Company websites, catalogs and other materials 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 user must correlate it to actual application requirements. Actual performance is subject to the Omron’s Warranty and Limitations of Liability.

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 part numbers when published ratings or features are changed, or when significant construction changes are made. However, some specifications of the Product may be changed without any notice. When in doubt, special part numbers may be assigned to fix or establish key specifications for your application. Please consult with your Omron’s representative at any time to confirm actual specifications of purchased Product.

Errors and Omissions

Information presented by Omron Companies has been checked and is believed to be accurate; however, no responsibility is assumed for clerical, typographical or proofreading errors or omissions.

Insulation Resistance Monitoring Device User’s Manual (N224)

Safety Precautions

Definition of Precautionary Information

The following notation is used in this manual to provide precautions required to ensure safe usage of the K7GE-MG Insulation Resistance Monitoring Device. 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.

CAUTION

Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury, or in property damage.

Symbols

Precautions for Safe Use

Precautions for Correct Use

Symbol Meaning

Caution

Prohibition

Mandatory

Caution

Precautions on what to do and what not to do to ensure safe usage of the product.

Precautions on what to do and what not to do to ensure proper operation and performance.

• General Caution Indicates non-specific general cautions, warnings, and dangers.

• Electrical Shock Caution Indicates possibility of electric shock under specific conditions.

• General Prohibition Indicates non-specific general prohibitions.

• Disassembly Prohibition Indicates prohibitions when there is a possibility of injury, such as from electric shock, as the result of disassembly.

• General Caution Indicates non-specific general cautions, warnings, and dangers.

Insulation Resistance Monitoring Device User’s Manual (N224)

Safety Precautions

CAUTION

Minor injury due to electric shock may occasionally occur. Do not touch the Product except for any buttons (keys) while power is being supplied.

Always connect the protective earthing terminal ( ) to a ground. Use AWG 16 for the protective conductor.

If the wiring material is inserted in a shallow position, it may cause property damage due to ignition. When wiring, make sure that the wiring material is properly inserted all the way into the terminal block.

If used the Product with incorrect wiring, it may cause property damage due to ignition. Make sure the cable is connected properly when the power supply is turned ON.

Minor electric shock, fire, or malfunction may occasionally occur. Do not allow metal objects, conductors, or cuttings from installation work to enter the Product.

Perform periodic inspection to the Product. A malfunction in the Product may occasionally prevent monitoring impossible or alarm outputs, resulting in property damage to connected equipment or devices. To maintain safety in the event of malfunction of the Product, take appropriate safety measures, such as installing a monitoring device on a separate line.

Minor injury due to explosion may occasionally occur. Do not use the Product where subject to flammable or explosive gas.

Minor electric shock, fire, or malfunction may occasionally occur. Do not disassemble, modify, or repair the Product or touch the interior of the Product.

Insulation Resistance Monitoring Device User’s Manual (N224)

Precautions for Safe Use

(1) Do not use or store the Product in the following locations:

• Outdoor or locations subject to direct sunlight

• Locations subject to rain and wind damage

• Locations subject to excessive vibration or shock

• Locations subject to rapid temperature changes

• Locations prone to icing and dew condensation

• Locations subject to water or oil

• Locations subject to dust or corrosive gases (particularly sulfurizing gases, ammonia, etc.)

• Locations subject to influence of static electricity and noise

• Locations subject to bugs and small animals

(2) A switch or circuit breaker should be provided close to this Unit. The switch or circuit breaker

should be within easy reach of the operator, and must be marked as a disconnecting means for this

Unit. (3) Mount the Product in the correct direction for installation. (4) Be sure to use power terminals carefully, because power supply terminals have hazardous voltage. (5) Use the wire given in this manual. (6) Use the power supply voltage within the range of the specifications and rated values. Use the input

voltage within the range of the specifications and rated values. (7) Make sure the crimp terminals for wiring are of the specified size. (8) Do not connect anything to terminals that are not being used. (9) Confirm the wiring the input and output terminals correctly before power is supplied. (10) The terminal block may be damaged if you insert a flat-blade screwdriver in the release hole with

excessive force. When inserting a flat-blade screwdriver into the release holes, operate with a

force of 15•N or less. (11) K7GE-MG may be subject to radio disturbances. Do not install the Product near equipment that

generates high frequencies or surges. (12) The maximum terminal temperature is 80°C. Use wires with a heat resistance of 80°C min to wire

the terminals. (13) Make sure the LCD and the LEDs for output indicators operate correctly. Depending on the

operating environment, the Product parts may deteriorate faster than expected, causing the

indicators to fail. (14) Use the cable within the length that is rated in the specification requirements for the wiring between

the sensor and the Product. As for the requirements on the cable distance, refer to 3-6 Wiring the

Communications Cable on page 3-13. (15) In order to prevent inductive noise, wire the lines connected to the Product separately from power

lines carrying high voltages or currents. Also, do not wire in parallel with or on the same cables as

power lines. Other measures for reducing noise are to separate from ducts including noisy lines. (16) Do not continue to use the Product if the front surface peels. (17) The alarm output function is a function for the output of an alarm when the set threshold value is

below. Do not use this function for control, etc. (18) Use this Product inside the control panel to prevent external noise. (19) When discarding the Product, properly dispose of it as industrial waste. (20) Never touch the charging terminal of the load while the K7GE-MG is in measurement operation. (21) K7GE-MG cannot be used for legal inspection. Be sure to use a periodically calibrated measuring

instrument for legal inspection. (22) When wiring, wire by enough length.

Insulation Resistance Monitoring Device User’s Manual (N224)

Precautions for Safe Use

(23) Check terminal polarity when wiring and wire all connections correctly. Do not wire the input and

output terminals incorrectly.

(24) K7GE-MG provides 50 VDC of Megger voltage. Do not use on equipment that may be damaged by

this voltage.

(25) Use and store the Product in a location where the ambient temperature and humidity are within the

specified ranges. If applicable, provide forced cooling.

(26) Please read and understand this manual before using K7GE-MG.

Insulation Resistance Monitoring Device User’s Manual (N224)

Precaution for Correct Use

Observe the following operating methods to prevent failure and malfunction. (1) During periodic inspection, installation of an additional sensor, or adjustment of sensor position,

use the Product after ensuring that correct operation can be performed. (2) When mounting K7GE-MG on a DIN Track, follow the installation method described in Mounting to

DIN Track on page 3-4 to install it correctly. (3) Confirm that wire does not stick up after wiring of stranded cable. (4) In case of crossover wiring, install these by 10 A per 1 terminal because when Products are

connected more than one in parallel, quite many electric currents to be called off. (5) The terminal block may be damaged if specialized tool is not used. Use a recommended flat-blade

screwdriver to inserted into a release hole on the terminal block. (6) This Product is designed for use by qualified personnel with a knowledge of electrical systems.

Read this manual carefully before using the Product. (7) Use the power supply voltage, input power, and other power supplies and transformers with

suitable capacities and rated outputs. (8) Use a power supply that will reach the rated voltage within 1 second after the power is turned ON. (9) Do not install the Product close contact with the heating element. (10) Do not install the Product near equipment that generates high frequencies or surges. (11) Install the Product so that the load doesn't span the Product body. (12) If an error occurs during K7GE-MG operation, stop operation immediately and make suitable

corrections such as replacement. (13) Do not use K7GE-MG for safety devices or applications that could result in loss of life. (14) Make sure to connect Main Unit and Probe Units before use. (15) Make sure that the number of additional Probe Units is within the specified range. (16) Be sure to install a magnetic contactor, etc. between the power supply and the load, and wire

K7GE-MG on the secondary side of it. (17) Do not turn ON power to the load while K7GE-MG is measuring. (18) Set the "Motor stop waiting time" setting value to at least the time from when the contactor is turned

off until the load completely stops. (19) If you accidentally drop K7GE-MG, the inside of the Product may be damaged, so do not use it. (20) Do not wire anything to the release holes. (21) Do not tilt or twist a flat-blade screwdriver while it is inserted into a release hole on the terminal

block. The terminal block may be damaged. (22) Insert a flat-blade screwdriver into the release holes at an angle. The terminal block may be

damaged if you insert the screwdriver straight in. (23) Do not allow the flat-blade screwdriver to fall out while it is inserted into a release hole. (24) Do not bend a wire past its natural bending radius or pull on it with excessive force. Doing so may

cause the wire disconnection. (25) Do not insert more than one wire into each terminal insertion hole. (26) Do not use any liquids such as paint thinner, similar solvents or alcohol to clean the Product. Clean

it with a soft, dry cloth.

Insulation Resistance Monitoring Device User’s Manual (N224)

Regulations and Standards

P1 P2

L1 L2

PEN

P2 P3

Conformance to Safety Standards

• For wiring from the Probe Unit to the load, use a Class CC, Class J, or Class T fuse with a rated current of 7A or less.

• The protection provided by the device may be impaired if the device is used in a manner that is not specified by the manufacturer.

• To use the Product, install it as an embedded device within a control panel.

• The table below shows the nominal voltage and measurement circuit connections available for each measurement category in the Main Power Supply System Configurations. Do not use the device under conditions that exceed this category and conditions.

Main Power Supply System Configurations

3-phase, 4-wire type (neutral point grounding)

3-phase, 3-wire type (no grounding)

3-phase, 3-wire type (single-phase grounding)

Regulations and Standards

Single-phase, 2-wire type AC or DC

Single-phase (split phase), 2-wire type AC or DC

TN-C-S

CAT III Phase voltage/line

voltage 277 V/480 V

Line voltage 300 V

P2 P3

Line voltage 300 V

Line voltage 240 V

Phase voltage/line voltage 240 V/480 V

CAT II 347 V/600 V in addition to

the above

Connection to measurement circuit

TT: Connect E in the diagram above to the No. 7 terminal (PE) of the K7GE-MGM. Connect P1 and P2 to the

480 V in addition to the above

Connect E in the diagram above to the No. 7 terminal (PE) of the K7GE-MGM. Connect P1 and P2 to the No. 1 and No. 3 terminals of the K7GE-MG1.

480 V in addition to the

Same as above

above

Connect E in the diagram above to the No. 7 terminal (PE) of the K7GE-MGM. Connect L1 and L2 to the No. 1 and No. 3 terminals of the

K7GE-MG1. No. 1 and No. 3 terminals of the K7GE-MG1.

TN-C-S: Connect PE in the diagram above to the No. 7 terminal (PE) of the K7GE-MGM. Connect L1 and L2 to the No. 1 and No. 3 terminals of the K7GE-MG1.

Insulation Resistance Monitoring Device User’s Manual (N224)

Regulations and Standards

Fixed equipment

Distribution board

CAT IV

CAT III

CAT IICAT I

Internal wiring

Service entry wire

Power

outlet

 Measurement Category

The measurement category classifies the places and equipment which you can connect to the measurement terminals, as prescribed in EN/IEC 61010-2-030. Each category is as follows.

CAT I: Equipment to connect to circuits where

measures are taken to limit transient overvoltages to low levels

CAT II: Energy-consuming equipment with an

energy supply from fixed wiring equipment (such as a power outlet)

CAT III: Equipment in fixed wiring equipment that

particularly demands equipment reliability and effectiveness

CAT IV: Equipment to use at the electrical service

entry

Conformance to EN/IEC Standards

This is a class A product. In residential areas it may cause radio interference, in which case the user may be required to take adequate measures to reduce interference.

Insulation Resistance Monitoring Device User’s Manual (N224)

Terminology

Ter m Abbreviation Description

CompoWay/F - CompoWay/F is OMRON's standard communications format for

FINS (Factory Interface Network Service)

Modbus RTU - This is a standard communications control method that conforms to

Channels CH The units of the insulation measurement loop for the Insulation

Power ON reset - A reset process that runs when the power turns ON.

Terminology

general serial communications. This format uses a standard frame format as well as the well-established FINS commands used for OMRON's PLCs. Therefore, it can simplify communications between components and the host.

FINS The FINS protocol provides message communications between

controllers in OMRON FA networks.

Modicon Inc.'s RTU-mode Modbus Protocol (PI-MBUS-300 Rev. J).

Resistance Monitoring Device.

Protective earthing PE The protective earth to connect to the housing of a device to bring

the housing to the same potential as the ground and allow ground fault currents to flow to ground.

K7GE-MG - "K7GE-MG" refers to the K7GE-MG with its Main Unit connected to

the Probe Units.

Megohmmeter - An instrument that measures the insulation resistance of electrical

products and indoor wiring, also called an insulation resistance meter.

Megger voltage - The voltage that the device applies to measure the insulation

resistance. The K7GE-MG applies 50 VDC.

Megger method - A method to measure resistance values by connecting a measuring

circuit between a ground-insulated charged section that is connected to the power line and a non-charged section such as a grounded motor frame.

Parasitic capacitance - The capacitance that exists between the charging terminal of the

load and the terminal such as between PE. Also called stray capacitance.

Insulation Resistance Monitoring Device User’s Manual (N224)

Manual Structure

Page Structure

Level 2 heading

Special information

Icons indicate precautions, additional information, or reference information.

Level 1 heading

Level 2 heading

Gives the current headings.

Page tab

Gives the number of the main section.

step in a procedure

Indicates a procedure.

Manual name

Icons

Special information in this manual is classified as follows:

Icon Meaning

No. **

Additional information to read as required. This information is provided to increase understanding or give hints on operation.

This indicates the position in Section 2 Procedure that provides more detailed information about trouble and countermeasures.

Insulation Resistance Monitoring Device User’s Manual (N224)

Revision History

N224-E1-01

Revision code

A manual revision code appears as a suffix to the catalog number on the front cover of the manual.

Revision code Date Revised content

01 January 2021 Original production

Revision History

Insulation Resistance Monitoring Device User’s Manual (N224)

Revision History

Insulation Resistance Monitoring Device User’s Manual (N224)

Overview

Installation and Wiring

Procedure

Functions Related to Measurement

Using Setting Parameters

Remote Monitoring

Troubleshooting

Appendices

Index

Sections in this Manual

Insulation Resistance Monitoring Device User’s Manual (N224)

Preface ...................................................................................................................... 1

Terms and Conditions Agreement .......................................................................... 2

Warranty, Limitations of Liability .................................................................................................................. 2

Application Considerations .......................................................................................................................... 3

Disclaimers .................................................................................................................................................. 3

Precautions...............................................................................................................4

Definition of Precautionary Information........................................................................................................ 4

Symbols....................................................................................................................................................... 4

Precautions for Safe Use......................................................................................... 6

Precaution for Correct Use......................................................................................8

Regulations and Standards.....................................................................................9

Conformance to Safety Standards............................................................................................................... 9

Conformance to EN/IEC Standards...........................................................................................................10

Terminology ............................................................................................................ 11

Manual Structure .................................................................................................... 12

Page Structure........................................................................................................................................... 12

Icons .......................................................................................................................................................... 12

Revision History .....................................................................................................13

Sections in this Manual .........................................................................................15

CONTENTS..............................................................................................................16

Section 1 Overview

1-1 Overview................................................................................................................................. 1-2

1-2 Features.................................................................................................................................. 1-3

1-3 Model Number Legend..........................................................................................................1-6

1-4 Insulation Resistance Measurement and Monitoring System........................................... 1-7

1-5 Nomenclature and Functions ............................................................................................... 1-8

1-6 Internal Block Diagram .......................................................................................................1-14

1-7 System Configurations ....................................................................................................... 1-16

1-8 Safety Precautions .............................................................................................................. 1-18

Section 2 Procedure

2-1 Procedure............................................................................................................................... 2-2

(1) Advance Preparation........................................................................................................................... 2-2

(2) Installation and Wiring.........................................................................................................................2-3

(3) Initial Setting........................................................................................................................................2-5

(4) Test Operation with Manual Measurement ......................................................................................... 2-7

(5) Starting Operation ............................................................................................................................... 2-8

Troubleshooting......................................................................................................................................2-10

Insulation Resistance Monitoring Device User’s Manual (N224)

Section 3 Installation and Wiring

3-1 Dimensions ............................................................................................................................ 3-2

3-2 Installation.............................................................................................................................. 3-3

3-3 Setting the Channel Number ................................................................................................ 3-6

3-4 How to Connect to the Push-In Plus Terminal Blocks ....................................................... 3-7

3-5 I/O Wiring.............................................................................................................................. 3-10

3-6 Wiring the Communications Cable .................................................................................... 3-13

3-7 Setting the Unit Number ..................................................................................................... 3-14

3-8 Connecting to a Load or Contactor ................................................................................... 3-15

Section 4 Functions Related to Measurement

4-1 Automatic Measurement....................................................................................................... 4-2

4-1-1 Trigger Input ............................................................................................................................... 4-2

4-1-2 Measurement Steps.................................................................................................................... 4-4

4-1-3 Measurement Step Indicator Operation ...................................................................................... 4-6

4-1-4 Timing Charts ............................................................................................................................. 4-8

4-1-5 Measurement Value Display Automatic Scroll.......................................................................... 4-16

4-2 Manual Measurement .......................................................................................................... 4-17

4-3 Measuring Range and Measuring Accuracy ..................................................................... 4-21

4-4 Voltage Monitoring .............................................................................................................. 4-22

4-5 Current Limiter..................................................................................................................... 4-23

4-6 Reset Key ............................................................................................................................. 4-25

4-7 System Error ........................................................................................................................ 4-26

4-8 Running Time....................................................................................................................... 4-27

4-9 Calculating the Measuring Time Using the Elapsed Time ............................................... 4-28

Section 5 Using Setting Parameters

5-1 Levels ..................................................................................................................................... 5-2

5-2 Setting Parameters and Setting Values............................................................................... 5-4

5-3 Maximum Number of Channels............................................................................................ 5-6

5-4 Alarm Values 1 and 2............................................................................................................. 5-9

5-5 Alarm Polarity ...................................................................................................................... 5-11

5-6 Trigger Signal Reverse........................................................................................................ 5-13

5-7 Motor Stop Waiting Time .................................................................................................... 5-15

5-8 Time to Wait to Stabilize...................................................................................................... 5-17

5-9 Average Processing ............................................................................................................ 5-19

5-10 Use Running Time ............................................................................................................... 5-21

5-11 Software Version ................................................................................................................. 5-23

5-12 Setting Change Protection ................................................................................................. 5-24

5-13 Communications Setting Parameters................................................................................ 5-26

Insulation Resistance Monitoring Device User’s Manual (N224)

Section 6 Remote Monitoring

6-1 Remote Monitoring................................................................................................................ 6-2

6-2 Communications Overview .................................................................................................. 6-3

6-3 Variable Area Map.................................................................................................................. 6-5

6-4 Monitoring (Reading) Measurement Values........................................................................ 6-8

6-5 Operation Command ............................................................................................................. 6-9

6-6 Checking (Reading) Setting Parameters ........................................................................... 6-12

6-7 Changing (Writing) Setting Parameters............................................................................. 6-13

6-8 CompoWay/F Communications Format ............................................................................ 6-14

6-8-1 Frame Configurations................................................................................................................6-14

6-8-2 Read Variable Area Command .................................................................................................6-17

6-8-3 Write Variable Area Command..................................................................................................6-18

6-8-4 Operation Command................................................................................................................. 6-20

6-9 Modbus RTU Communications Format ............................................................................. 6-22

6-9-1 Frame Configurations................................................................................................................6-22

6-9-2 Read Variable Area Command .................................................................................................6-25

6-9-3 Write Variable Area Command..................................................................................................6-26

6-9-4 Operation Command................................................................................................................. 6-27

Section 7 Troubleshooting

7-1 Troubleshooting .................................................................................................................... 7-2

Appendices

A-1 Specifications ........................................................................................................................A-2

Ratings and Specifications .......................................................................................................................A-2

Measurement Specifications.....................................................................................................................A-3

Input Specifications of Trigger Input Terminals ........................................................................................A-3

Output Specifications of Transistor Output Terminals ..............................................................................A-4

Input Specifications of Voltage Input Terminals........................................................................................A-4

Communications Specifications................................................................................................................A-5

A-2 Setting Parameters List ........................................................................................................A-6

A-3 Setting Parameter Flow.........................................................................................................A-7

A-4 K7GE-MG Logging Tool ........................................................................................................A-8

Index

Insulation Resistance Monitoring Device User’s Manual (N224)

Overview

This section describes the features, model number legend, nomenclature and functions, system configuration, and safety precautions of the K7GE-MG.

1-1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1-2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

1-3 Model Number Legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

1-4 Insulation Resistance Measurement and Monitoring System . . . . . . . . . . 1-7

1-5 Nomenclature and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

1-6 Internal Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

1-7 System Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

1-8 Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 1

1 Overview

Probe Unit

K7GE-MG1

Main Unit

K7GE-MGM

Probe Unit Probe Unit Probe Unit

Main Unit

1-1 Overview

The K7GE-MG is a device that automatically measures the insulation resistance of a load and supports trend monitoring.

Periodic inspections by manpower may cause a unexpected machine stoppage due to a decrease in insulation resistance of equipment before the next inspection. The K7GE-MG provides automatic monitoring of the insulation resistance of each load and allows planned maintenance.

The K7GE-MG measures the insulation resistance by the same detection principle (Megger method) as a Megohmmeter.

To measure the insulation resistance using the K7GE-MG, it is necessary to combine one Main Unit with at least one Probe Unit.

The functions of the Main Unit and Probe Unit are shown in the figure on the right.

The Main Unit corresponds to a Megohmmeter, and the Probe Unit corresponds to a measurement probe with internal contacts. The Main Unit turns ON these contacts in sequence and measure multiple loads individually.

Up to eight Probe Units can be connected to one Main Unit.

K7GE-MG supports a motor as a measurement load. If you want to measure other loads such as a heater or transformer, carefully study the operating specifications of the K7GE-MG before use.

1 - 2

Insulation Resistance Monitoring Device User’s Manual (N224)

1-2 Features

Note The above diagram shows only the parts of the internal circuit of the K7GE-MG that are

necessary for explanation.

The following features make the K7GE-MG convenient and safe to use.

Uses the Same Detection Principle as a Megohmmeter

1 Overview

1-2 Features

The K7GE-MG measures the insulation resistance by the same detection principle

Megger method

(Megger method) as a Megohmmeter. Therefore, the inspection data of the Megohmmeter can be used, and the smooth introduction of this system is possible.

Megohmmeter

K7GE-MG

More Support for the Safety Functions

• The K7GE-MG is always monitoring the OFF state of the loads and the power line. K7GE-MG does

not start measurement even if it receives a measurement start signal during load operation. In addition, K7GE-MG will stop the measurement immediately if the load restarts during the measurement.

• In addition, the K7GE-MG is

equipped with an overcurrent limit circuit. This limits the following overcurrents to safe levels:

- Instantaneous overcurrent that flows when the load is restarted during measurement.

- Overcurrent that flows when the insulation resistance value is extremely low.

MC MC-a

Interlock

Turn OFF

Auxiliary

OFF

contact

L2 L3

Status output

during

measurement

K7GE-MG

Current

limiter

Megger voltage (50 VDC)

Voltage

monitoring

Overcurrent

prevention

Disconnection (turn OFF) monitoring

Disconnection (turn OFF) OK

Start measurement

• To reduce equipment damage

and prevent electric shock, the K7GE-MG has a low Megger voltage of 50 VDC*.

* Even if the Megger voltage is 50 VDC, it does not affect the measurement accuracy.

• The K7GE-MG provides a contact output that indicates that measurement is in progress. You can

design an interlock circuit that prevents the load from restarting during the measurement.

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 3

1 Overview

K7GE-MG

8 Units max.

Note The above diagram shows only the parts of the internal

circuit of the K7GE-MG that are necessary for explanation.

K7GE-MG

Contact OFF except during measurement

Megohmmeter

Measurement current of the Megohmmeter does not flow

Control panel

Trigger input

MC-a

Supports Multiple Channel Measurement

K7GE-MG can be measured up to eight channels per Main Unit by adding more Probe Units. This reduces cost and installation space per channel.

Periodic Inspection by a Megohmmeter Is Possible with the K7GE-MG Installed

The K7GE-MG is cut off from the load by the internal dry contact except during measurement. This allows inspection using a Megohmmeter without disconnecting the wiring.

Easy Retrofitting to the Equipment

• The signal wire of the K7GE-MG can be connected in parallel with the

secondary output terminal of the contactor and the PE terminal of the load. Therefore, it is not necessary to perform large-scale wiring again.

• If you connect the auxiliary contact of the contactor to the trigger input

terminal of the K7GE-MG, you can use it as a measurement start signal. It contributes to the reduction of parts because no additional sequence is required.

1 - 4

Insulation Resistance Monitoring Device User’s Manual (N224)

Enables Remote Trend Monitoring

• K7GE-MG automatically collects the measured

values of loads with the communications function. You can monitor the equipment from a remote location. Remote monitoring greatly reduces the man-hours required to measure and collect data with the Megohmmeter while patrolling FA systems and facilities.

Measurement

value

Alarm value 1

Alarm value 2

'xx/ 1 2 3 4 5 6 7 Year/Month

Communications converter

Load 1

Load 2

Load 3

1 Overview

1-2 Features

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 5

1 Overview

K7GE-MG M

□

(1) (2) (3)

K7GE-MG 1

(1) (2)

1-3 Model Number Legend

This section shows the model number legend of the K7GE-MG Main Unit and Probe Units.

• Main Unit

(1) (2) (3) Meaning

Base model Unit type Power supply voltage

K7GE-MG Insulation Resistance Monitoring Device

M Main Unit

A 100 to 240 VAC power supply

D 24 VAC/VDC power supply

• Probe Unit

(1) (2) Meaning

Base model Unit type

K7GE-MG Insulation Resistance Monitoring Device

1 Probe Unit

Refer to A-1 Specifications on page A-2 for the specifications of each model.

1 - 6

Insulation Resistance Monitoring Device User’s Manual (N224)

1 Overview

Note The above diagram shows only the parts of the internal

circuit of the K7GE-MG that are necessary for explanation.

1-4 Insulation Resistance Measurement

and Monitoring System

K7GE-MG is automated according to the procedure of manual measurement and monitoring by Megohmmeter. The flowchart of measurement and monitoring of K7GE-MG is shown below together with manual measurement by Megohmmeter.

MC-a

Auxiliary

contact

OFF

K7GE-MG

Start measurement

Discharge of electric charge

Apply Megger voltage

surement and Monitoring System

1-4 Insulation Resistance Mea-

Megohmmeter

Step Manual measurement by the Megohmmeter Step Automatic measurement by the K7GE-MG

Load operation in progress

Turn OFF the contactor and disconnect the loads from

the power line

Waits until the auxiliary contact turns OFF (trigger

signal ON)

Trigger signal ON with the contactor OFF → Measurement operation starts when the trigger

signal is ON

Waits for the loads to stop completely

Wait for the loads to stop completely (visual)

(automatic standby based on setting parameters,

default value: 10 s)

Wait for the discharge of electric charge accumulated in the wiring

(Decide the time through experience or residual voltage measurement)

Place the probe on the load and apply Megger voltage

Performs forced discharge of electric charge by the built-in resistor of the K7GE-MG

(Waits for 20 s while limiting the peak value of the discharge current to 1 mA max.)

Internal contact of the Probe Unit turns ON, and

application of the Megger voltage starts

Applies Megger voltage until the measurement value

Wait for the measurement value to stabilize (charging

time to the wiring capacity)

stabilizes (Continues the measurement for the time set in the

Time to Wait to Stabilize setting parameter, default value: 60 s)

Read the insulation resistance value

Remove the probe from the load

Determine if the measurement value is normal or an

error

If there is more than one load, measure the next load

Record the measurement value and end the series of

operations

Insulation Resistance Monitoring Device User’s Manual (N224)

Measures the insulation resistance value

The contact of the Probe Unit turns OFF, and

application of the Megger voltage stops

Compares the set alarm value and measurement

value, and performs alarm output

If there is more than one load, measures the next load

Check the measurement value from the display on the

front part, or read and record it remotely

1 - 7

1 Overview

(A)

(B)

(C)

(D)

(E)

(A)

(B)

(C)

Main Unit Probe Unit

1-5 Nomenclature and Functions

Appearance

Symbol Name Operation

(A) DIN Track mounting hook Used for mounting to the DIN Track.

(B) Right connector Connects the Probe Unit.

Remove this cover when combining the Main Unit and Probe Units, and during expansion of Probe Units. However, use the Probe Unit on the extreme right without removing this connector cover.

(D) Left connector cover A cover for preventing the entry of dust and dirt into the connectors.

Remove this cover when combining the Main Unit and Probe Units, and during expansion of Probe Units.

(E) Left connector Connects to the Right connector.

1 - 8

Insulation Resistance Monitoring Device User’s Manual (N224)

Front Section: Main Unit

(A)

(B)

(C)

(D)

(E)

(F)(G)(H)

(I)

(J)

Symbol Name Operation

(A) Alarm output

indicator

Displays the alarm judgment results of automatic measurement in three colors. Green: Normal Yellow: Warning (Alarm 1 occurrence) Red: Critical (Alarm 2 occurrence) If the status is different across multiple channels, the display color is decided in the priority order of red (critical) > yellow (warning) > green (normal).

1 Overview

1-5 Nomenclature and Func-

tions

(B) Measurement

step indicator

The automatic measurement operation consists of several steps. This indicator shows the progress of the step from the start to the end of the measurement.

Measuring operation: The remaining seconds until the measurement

completes are counted down

After measurement completed: The insulation resistance measurement value, or

characters indicating measurement failure Setting level: The setting parameter name, or setting value Error occurs: The characters indicating the error status

(D) Protect indicator Indicates that the protect function of the setting parameter is set.

(E) Operation keys

Level Key ( )

Mode Key ( )

Selects the setting level.

Selects the setting parameter of the Initial Setting Level and Communications Setting Level. Displays the measurement value of each channel at the Operation Level. Also used to select between enabling/disabling of measurement value display automatic scroll.

Shift Key ( )

Sets the parameter value to a changeable state. Used for digit shift in the changeable state.

Up Key ( )

(F) Manual

Measurement Key

Selects to start or end manual measurement. Manual measurement is used to check the operation when the system is started up. Automatic measurement requires a trigger signal to start measurement, but manual measurement does not require a trigger signal. You can use manual measurement in the same way as a Megohmmeter.

Increments the value when the parameter is in a changeable state.

(G) Reset Key Selects to return to the power reset status. Even if the measuring operation is in

progress, priority is given to the Reset Key, and measurement stops to return to the power reset status. The Reset Key is enabled only in the Operation Level.

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 9

1 Overview

Symbol Name Operation

(H) Unit Number

(I) Status display MANU Indicates the manual measurement state.

(J) LVL/CH display Displays the level*, or the value of the channel number.

* Refer to 5-1 Levels on page 5-2 for information on the levels.

Sets to set the unit number during communications.

Setting Switch

ERR Indicates that a system error occurred.

AGE Indicates that it is time to replace the Main Unit (guideline).

LVL Indicates that the value displayed in the LVL/CH display is the

"Level".

CH Indicates that the value displayed in the LVL/CH display is the

"Channel".

1 - 10

Insulation Resistance Monitoring Device User’s Manual (N224)

+ 142 hidden pages