OMRON K7GE-MG User Manual

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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)

1 Overview

(A)

(B)

(C)

(D)

1-5 Nomenclature and Func-

Front Section: Probe Unit

tions

Symbol Name Operation

(A) PWR indicator (green) Indicates that the Probe Unit power is ON.

(B) MEAS indicator (green) Indicates that measurement is in progress for the load connected to

the Probe Unit.

Unit.

(D) Channel Number Setting

Switch

Sets a unique channel number for each Unit when multiple Probe Units are added.

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 11

1 Overview

(A)

(E)

(D)

(B)

(C)

(H)

(I)

(F)

(G)

Terminal Section: Main Unit

Symbol

(A) 1 and 2 Operation

Terminal

Number

Name Operation

Connect the operation power supply to the Main Unit.

power supply

(B) 3 and 4 Trigger input Input terminals of the external contact from where a trigger signal is

applied. No. 3: Collector of the NPN transistor, No. 4: Emitter of the NPN transistor

No. 5: +, No. 6: -

(D) 7 PE A protective earthing terminal.

(E) NC NC Do not connect anything to this terminal.

(F) 13 and 14 ALM 1 output Compares the measurement value and alarm value 1, and outputs an

alarm. No. 13: Collector of the NPN transistor, No. 14: Emitter of the NPN transistor

(G) 15 and 16 ALM 2 output Compares the measurement value and alarm value 2, and outputs an

alarm. No. 15: Collector of the NPN transistor, No. 16: Emitter of the NPN

(H) 17 and 18 Status output

during measurement

transistor

Provides notification that measurement is in progress. The output is normally open (OFF) You can use this output to design an interlock circuit to prevent accidental restart of the load during measurement operation. No. 17: Collector of the NPN transistor, No. 18: Emitter of the NPN transistor

(I) 19 and 20 Self-diagnosis

error output

Provides notification about system error in the Main Unit. The output is normally closed (ON). No. 19: Collector of the NPN transistor, No. 20: Emitter of the NPN transistor

1 - 12

Perform the wiring according to Section 3 Installation and Wiring.

Insulation Resistance Monitoring Device User’s Manual (N224)

Terminal Section: Probe Unit

(A)

(B)

1 Overview

1-5 Nomenclature and Func-

tions

Symbol

Terminal

Number

Name Operation

(A) 1 and 3 Voltage input Connect the load terminals.

No. 1: Connect the R-phase in a 3-phase system, and the

L-phase in a single-phase system

No. 3: Connect the S-phase in a 3-phase system, and the

N-phase in a single-phase system Use the terminal No. 1 to discharge the electric charge and apply the Megger voltage.

(B) NC NC Do not connect anything to this terminal.

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 13

1 Overview

1-6 Internal Block Diagram

This is an internal block diagram of the state when the Main Unit and the Probe Units are connected. The following describes the main configuration elements.

RS-485

ALM 1 and ALM 2

outputs

Self-diagnosis

error output

Status output during

measurement

Display

switch

RS-485

driver

Trigger

input

Microcomputer

Measurement

Megger voltage

Current

limiter

Power supply

Probe Unit 1Main Unit

Discharge of electric charge

MGR

I/O Bus

MC-a

Megger

Apply

voltage

L3PE

Voltage

monitoring

Probe

Unit

control

Display

switch

Probe Unit 2

...

 Trigger Input

Connect an external contact, and then starts the measurement operation by a signal from this contact. When the auxiliary contact of a contactor is connected to a trigger input terminal as an external contact, the measurement operation can be started at the time the contactor is turned OFF, that is, when the load is turned OFF from the power line.

 Voltage Monitoring

The voltage in the load lines is monitored to determine whether the load is turned ON or turned OFF. This monitoring is performed at all times, and even when the measurement start signal is input, the measurement operation does not start if the load is turned ON. Also, even if measurement is progressing normally, it immediately stops if the load is turned ON during the measurement.

 Discharge of Electric Charge

A parasitic capacitance component due to the wiring is present between the charged sections of the load and the PE. Therefore, even if the contactor is turned OFF, the electric charge accumulated in the parasitic capacitance component is not discharged immediately. It would take several minutes for the electric charge to be discharged naturally, so this circuit forcibly discharges the charge. In the case of a simple short circuit, excessive short-circuit current flows instantaneously, and therefore, by having a resistance component, the current can be limited to a level where it does not cause any problem. This processing for the discharge of electric charge is performed before the application of a Megger voltage.

1 - 14

Insulation Resistance Monitoring Device User’s Manual (N224)

1 Overview

 Megger Voltage

Generates a voltage of 50 VDC.

 Apply Megger Voltage

Turns ON the internal contact and applies Megger voltage to the load.

 Measurement

Measures the current flowing through the insulation resistance. Since Megger voltage is a known value, the insulation resistance value can be calculated from the Megger voltage and the current value.

 Current Limiter

If the load is turned ON when applying a Megger voltage, it is detected by the voltage monitoring circuit and the measurement operation stops. However, due to a slight time lag, excessive current flows between the charged sections of the load and the PE at the moment the load is turned ON. The same thing happens when the insulation resistance value is extremely low even if the load is properly turned OFF. To protect the load and the peripheral equipment, as well as the internal circuit of the K7GE-MG from such an overcurrent, the K7GE-MG is equipped with a current limiter circuit which limits the overcurrent.

1-6 Internal Block Diagram

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 15

1 Overview

MC-a

Measurement start signal

Status output during measurement

Alarm output

Interlock

Measurement starts at auxiliary contact OFF

Alarm output

MC MC

MC-a

Measurement start signal

Status output during measurement

Interlock

Measurement starts at auxiliary contact OFF

1-7 System Configurations

Minimum Configuration

This is the minimum configuration for monitoring the insulation resistance using the K7GE-MG.

The auxiliary contact of the contactor inserted in front of the load can be used as the measurement start signal (trigger signal).

You can check the measurement value from the display on the front part.

The alarm output can be used for external notification. There are two alarm outputs, and by setting a threshold value for each alarm output, judgment can be performed in two stages.

The K7GE-MG has the "Status output during measurement" terminal that is turned on during measurement operation. This allows you to design an interlock circuit that will not restart the load during measurement operation.

Measurement of Multiple Channels

This configuration is used when monitoring multiple loads collectively.

Design a system configuration that simultaneously turns ON and OFF the contactors installed on the loads. The K7GE-MG performs sequential measurement for one load at a time upon receiving the measurement start signal (trigger signal). However, a load that is turned ON at the time of measurement is treated as "measurement failed".

In an application such as a duplex alternating pump, you can use the K7GE-MG by constructing a sequence in which a trigger signal is input at the time all loads (pumps) are simultaneously OFF (when neither water supply nor draining is performed). In cases where it is not possible to realize the timing when all loads are simultaneously OFF, use two sets of the K7GE-MG Main Unit + Probe Units.

1 - 16

Insulation Resistance Monitoring Device User’s Manual (N224)

1 Overview

Remote Monitoring by the PLC or PC

This configuration is used when performing remote monitoring of the measurement values with a PLC or PC as the host.

1-7 System Configurations

When a PC is used as the host, you can use the K7GE-MG by converting the

Communications

converter

RS-485 to USB or Ethernet using a commercial communications converter.

The protocol is compatible with CompoWay/F and Modbus RTU.

The K7GE-MG does not have a function to retain the past measurement value data.

31 Node max. 500 m max.

RS-485

Also, data is lost when the power is turned OFF. Therefore, read the measurement values when the measurement ends and before the next measurement starts, and before the power of the Main Unit is turned OFF.

To know the timing of measurement end, you can use status output during measurement in the K7GE-MG. Status output during measurement turns ON when the measurement operation starts and turns OFF when measurement ends. This change from ON to OFF is the timing when measurement ends. You can also use the communications commands to read the flags synchronous with the status output during measurement.

PLC

Customization of HMI from the Touch Panel

This configuration is used when a touch panel is installed on the front panel to customize the HMI for checking the measurement values and performing the alarm reset operation.

A connection is established with the touch panel via the RS-485, and the touch panel is used as the master.

The protocol is compatible with CompoWay/F and Modbus RTU.

The K7GE-MG does not support the multi-master system. Therefore, to further connect a host system and perform remote monitoring, connect the host system to the touch panel, and perform operations such as reading the measurement values or changing the setting parameters of the K7GE-MG via the touch panel.

Refer to the manual of the touch panel in use for details on communications between the host system and the touch panel.

Touch panel OMRON NB-series, etc.

USB or

Ethernet

PLC

RS-485

Insulation Resistance Monitoring Device User’s Manual (N224)

1 - 17

1 Overview

Incorrect Correct

Inverter

K7GE-MG

Inverter

Contactor

Incorrect Correct

1-8 Safety Precautions

Be sure to install the contactor in front of the load to be measured.

The K7GE-MG uses the same Megger method as a Megohmmeter for detecting insulation resistance. The Megger method measures resistance values with a measuring circuit connected between the charged section and the non-charged section. The charged section is usually connected to the power line and insulated from the ground. Also, the non-charged section is a grounded section such as a motor frame. The measurement circuit of K7GE-MG is connected between different insulated circuits. Therefore, if the charged sections turn ON during measurement, it may result in a ground-fault accident.

K7GE-MG

Contactor

K7GE-MG

Also, although the voltage is low, applying a Megger voltage to the output circuit of the secondary coil of the inverter may cause an inverter failure.

1 - 18

Insulation Resistance Monitoring Device User’s Manual (N224)

Procedure

This section describes the procedure from preparation to startup of the K7GE-MG.

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)

2 - 1

2 Procedure

MC MC MC

MC-a

Measurement starts at auxiliary contact OFF

Status output during measurement

Alarm output

Measurement start signal

Interlock

2-1 Procedure

The procedure for starting actual operation is shown using a system that measures three loads as an example. The procedure is described in the following five steps.

Steps

(1) Advance Preparation

(2) Installation and Wiring

(3) Initial Setting

(4) Test Operation with Manual Measurement

(5) Starting Operation

The " No. **" in the following description is the reference number in Troubleshooting at the end of this section. Refer to the corresponding number when the operation does not run normally even after following the procedure.

(1) Advance Preparation

Examine the time until the load stops.

• Measure the time until the load stops after the contactor is turned

OFF. Use the setting value of the Motor Stop Waiting Time setting parameter as a guide.

Use the value of the load that took the longest time from among the three loads as a guide.

Use a Megohmmeter to measure the insulation resistance during normal operation of the target load.

2 - 2

• This is the reference value for deciding the Alarm Value 1 and 2

setting parameters.

Insulation Resistance Monitoring Device User’s Manual (N224)

(2) Installation and Wiring

*Sold separately

Connect three Probe Units to one Main Unit.

• Remove the right connector cover of the Main Unit and the left

connector cover of the Probe Units.

Use the Probe Unit on the right end with the right connector cover attached.

2 Procedure

2-1 Procedure

• Join the connectors together. Make sure that the connectors are

connected firmly without any gap between the Units.

Mounting to DIN Track.

• Pull down the DIN Track mounting hook under the Main Unit and

Probe Units to mount the Units on the DIN Track.

• Secure with the DIN Track mounting hook.

• Install an end plate* on the left and right sides.

Be sure to connect the Units together before mounting them on the DIN Track.

End plate

DIN Track mounting hook

Insulation Resistance Monitoring Device User’s Manual (N224)

2 - 3

2 Procedure

MC-a

L3 L2 L3 L2 L3 L2

17 18

13 14 15 16

Main Unit

Trigger

input

Operation power supply

Status output during measurement

ALM 1 ALM 2

17 18

1 3 1 33 4 1 3

M M

Probe Unit 1 Probe Unit 2 Probe Unit 3

Wire all connections.

• To be safe, always attach a

fuse (2 A max., fast-blow type) in the wiring from the Probe Unit to the load.

• The figure shows a

simplified view of the wiring for status output during measurement, and ALM 1 and ALM 2 outputs. Use a suitable relay according to the switching capacity of the output transistor.

• The K7GE-MG provides an

output transistor with specifications of 24 VDC (+10%) and 50 mA max.

Supply the operation power from a system different from that of the load. If the same system is used, the power supply to the K7GE-MG will turn OFF when the load contactor turns OFF, and you may not be able to perform measurement.

2 - 4

Insulation Resistance Monitoring Device User’s Manual (N224)

(3) Initial Setting

* This is reference number in Troubleshooting described at

the end. If the K7GE-MG does not operate properly after performing the procedure, see the reference number.

Set the channel numbers of the Probe Units.

• Set the channel number of the first Probe Unit to 1 with the rotary

DIP switch on the front.

Observe that it is not a DIP switch on the Main Unit side.

2 Procedure

2-1 Procedure

• In the same way, set the channel number of the second Probe

Unit to 2 and that of the third Probe Unit to 3.

Always set the channel number to a serial number starting from 1. The K7GE-MG will not operate properly if the channel numbers are not set sequentially from 1 such as 2, 3 and 4 or 1, 2 and 4.

Turn ON the power supply to the Main Unit.

• The Operation Level is displayed immediately after the power is

turned ON.

---- indicates measurement standby.

Move to the Initial Setting Level.

• Press the Level Key for at least 3 seconds to move from the

Operation Level to the Initial Setting Level. In the Initial Setting Level, LVL and 0 are displayed together on the LVL/CH display.

No.1*

3 seconds

TRIG FIN

LVL

----

MANU ERR AGE

TRIG FIN

LVL

mxch

MANU ERR AGE

Set the total number of channels.

The total number of channels is used to perform the processing in the case of a measurement failure when the Main Unit can no longer recognize the Probe Units due to a malfunction, etc.

• If the main display part does not display mxch, press the Mode

Key several times to display mxch.

• Press the Shift Key to display the setting value.

The setting value is displayed.

Insulation Resistance Monitoring Device User’s Manual (N224)

TRIG FIN

LVL

mxch

MANU ERR AGE

TRIG FIN

LVL

MANU ERR AGE

2 - 5

2 Procedure

TRIG FIN

LVL

MANU ERR AGE

TRIG FIN

LVL

MANU ERR AGE

alm1

TRIG FIN

LVL

MANU ERR AGE

1 second

----

TRIG FIN

LVL

MANU ERR AGE

• Press the Shift key again to change the setting value.

• Press the Up Key several times to set the setting value to 3.

• Press the Mode Key to define the changes.

Repeat the process to set the other parameters.

The digits that can be changed start flashing.

In this example, the total number of channels is set to 3 because three Probe Units are used.

The setting value is overwritten, and the next setting parameter will be displayed.

Parameter name Characters Setting value Description

Alarm Value 1 alm1 xx.x (MΩ) If the measurement value dropped below the alarm

value, the alarm output indicator is lit yellow and ALM 1 (warning) will be output. One alarm value 1 is provided in common for all channels.

Alarm Value 2 alm2 xx.x (MΩ) If the measurement value dropped below the alarm

value, the alarm output indicator is lit red and ALM 2 (critical) will be output. One alarm value 2 is provided in common for all channels.

Motor Stop Waiting Time

If you want to use a user-specified critical threshold, set it to alarm value 2. Alarm value 1 is set between the normal value measured during advance preparation and alarm value 2. If you do not have a user-defined critical threshold, the alarm value 2 can be set to 1 MΩ recommended by IEC 60034-1 and the motor manufacturer. Alarm value 1 is set between the normal value measured during advance preparation and alarm value 2.

mtwt xxx (seconds) Set the time until the load stops after the contactor

turns OFF plus a margin. (Use the time measured during advance preparation as a guide.)

Return to the Operation Level.

• Press the Level Key for at least 1 second to return to the

Operation Level.

---- indicates measurement standby.

No.2

2 - 6

Insulation Resistance Monitoring Device User’s Manual (N224)

(4) Test Operation with Manual Measurement

----

TRIG FIN

LVL

MANU ERR AGE

MANU

After xx seconds

TRIG FIN

LVL

ERR AGE

9#4

Make sure the load contactor is turned OFF.

• Immediately after returning to Operation Level, the

measurement standby is established without starting measurement even if the auxiliary contact of the contactor is turned OFF. Perform manual measurement in this state.

Select the channel to perform manual measurement.

2 Procedure

2-1 Procedure

No.3

• Press the Mode Key several times to set the channel number to

perform manual measurement.

Manual measurement is started.

• Press the Manual Measurement Key at least for 3 seconds to

start manual measurement. MANU indicator will light.

• Manual measurement performs continuous monitoring

regardless of the trigger signal, and does not provide ALM 1 and ALM 2 outputs.

Make sure the measurement value is suitable.

• Make sure the measurement value stabilizes within 60 seconds.

If the measurement value does not stabilize even within 60 seconds, return to the Initial Setting Level, and increase the setting value of the Time to Wait to Stabilize (stwt) setting parameter. Up to 99 seconds can be set. This setting value is used for the waiting time from when a Megger voltage is applied during automatic measurement until the measurement value stabilizes.

No.4

No.5

MANU MEAS

3 seconds

Measurement value

Within 60 seconds?

TRIG FIN

LVL

----

MANU ERR AGE

TRIG FIN

LVL

7"6

MANU

ERR AGE

• Make sure that the measurement value is not significantly

different from the value previously measured with the Megohmmeter.

If the measurement value is not stable due to the influence of noise, change the setting value of the Average processing (avg) setting parameter to ON (with averaging processing) in the Initial Setting Level. When this parameter is set to ON, the average value of eight measurements is treated as the measurement value.

Insulation Resistance Monitoring Device User’s Manual (N224)

No.6

2 - 7

2 Procedure

MANU

MANU MEAS

TRIG FIN

LVL

ERR AGE

1 second

----

MANU

TRIG FIN LVL

ERR AGE

--96

CH1 CH2 CH3

MANU

TRIG FIN LVL

ERR AGE

--81

CH1 CH2 CH3

MANU

TRIG FIN LVL

ERR AGE

--61

CH1 CH2 CH3

MANU

TRIG FIN LVL

ERR AGE

--61

CH1 CH2 CH3

Manual measurement is ended.

• Press the Manual Measurement Key for 1 second to end

manual measurement, and the K7GE-MG will return to measurement standby in the Operation Level. In addition, the measurement will be ended automatically 3 minutes after the start of manual measurement.

Perform manual measurement for the remaining channels as well.

• Repeat the process to perform manual measurement for the

remaining channels as well, and check the measurement values.

(5) Starting Operation

Turn ON the load contactor.

• Make sure the peripheral equipment including loads are

operating correctly.

Turn OFF the load contactor.

• Automatic measurement is started.

TRIG indicator will light on the measurement step indicator. The main display part shows the approximate number of seconds required to complete the measurement, and it will be counted down.

• The discharge of electric charge is performed after the time set

in the Motor Stop Waiting Time setting parameter has elapsed. The measurement step indicator moves to the next step. The first arrow indicates that the discharge of electric charge is in progress. The MEAS indicator on channel 1 of the Probe Unit will light in measurement operation. This process always requires 20 seconds.

2 - 8

• A Megger voltage is applied and it is held for approximately 60

seconds until the measurement value stabilizes. The measurement step indicator moves to next step. The second arrow indicates waiting for stability.

• Sampling is performed. It takes about 1 second.

The measurement step indicator moves to next step. The third arrow indicates that measurement is in progress.

Insulation Resistance Monitoring Device User’s Manual (N224)

• The measurement of channel 1 is completed, the alarm

MANU

TRIG FIN LVL

ERR AGE

--81

CH1 CH2 CH3

judgment is performed for the confirmed measurement value, and the results are applied in the alarm output, the alarm output indicator, and the ALM indicator of the Probe Unit. Next, the measurement for channel 2 will start. The MEAS indicator on channel 2 of the Probe Unit will light. You can perform the Motor Stop Waiting Time setting parameter only during the first measurement. The procedure for channel 2 onward will be started from the discharge of electric charge.

• When the measurement is complete for all channels, the

confirmed measurement values are displayed on the main display part. FIN indicator will light on the measurement step indicator.

Check the results of automatic measurement.

TRIG LVL

-9#2

ERR AGE

MANU

2 Procedure

FIN

CH1 CH2 CH3

2-1 Procedure

• Press the Mode Key to display the measurement results of

each channel.

Start actual operation.

• Start actual operation if there is no problem in the series of

operations of the K7GE-MG and the operation of peripheral equipment including loads and the measurement values.

No.7

TRIG LVL

-9&8

ERR AGE

MANU

TRIG LVL

-8'4

MANU

ERR AGE

TRIG LVL

-9#2

MANU

ERR AGE

FIN

Insulation Resistance Monitoring Device User’s Manual (N224)

2 - 9

2 Procedure

8888

TRIG FIN

LVL

MANU ERR AG E

psel

TRIG FIN

LVL

MANU ERR AGE

MANU

TRIG FIN LVL

ERR AGE

--81

MANU

TRIG FIN

LVL

ERR AGE

trig

FIN

MANU

TRIG

LVL

ERR AGE

-----

5 s

MANU

LVL

ERR

MANU

LVL

ERR

Troubleshooting

If the K7GE-MG does not operate properly after performing the procedure, see the correction in the table below corresponding to the reference number " No. **" in the procedure.

No. Problems Cause Correction

1 ERR indicator is lit,

2 psel is displayed

3 TRIG indicator

A system error occurred.

and 8888 is displayed.

The channel numbers of the Probe Units may be duplicated.

The Level Key ( ) was

in the LVL 1.

pressed for less than 1 second, which caused the K7GE-MG to move to the Communications Setting Level.

After returning to the lights on the measurement step indicator, and countdown of seconds starts on the main display

Operation Level, the auxiliary

contact of the contactor is

turned OFF, so the trigger

signal is accepted and

automatic measurement is

started. part.

trig flashes. After returning to the

Operation Level, the auxiliary

contact of the contactor is

turned OFF, so the trigger

signal is accepted and

automatic measurement is

started. However, the auxiliary

contact is immediately turned

ON and the measurement is

interrupted.

Check again that the channel numbers of the Probe Units are correctly set to consecutive numbers starting from 1.

Press the key for at least 1 second. Press the Level key

( ) for at least 1 second to return to the Operating Level even in the Communications Setting Level.

Press the Reset Key for at least 3 seconds to forcibly end the measurement. If the trigger signal occurs unintentionally, check the wiring of the trigger input terminal again.

You can perform manual measurement even in this state. If the trigger signal occurs unintentionally, check the wiring of the trigger input terminal again.

2 - 10

4 The channel display does not change

even after pressing the Mode Key ( ).

The Maximum Number of

Channels setting parameter

may not be set correctly.

The channel display is scrolled automatically every 5 seconds.

The Mode Key ( ) was

pressed for 3 seconds, which

resulted in measurement

value display automatic scroll.

Insulation Resistance Monitoring Device User’s Manual (N224)

Check again that the setting value is set to 3, which is the total number of Probe Units.

Press the Mode Key ( ) again for 3 seconds to cancel automatic scroll.

2 Procedure

FIN

MANU

TRIG

LVL

ERR AGE

-----

No. Problems Cause Correction

5 The manual

measurement does not start but the main display part flashes when the Manual Measurement Key is pressed.

Even if MANU indicator is lit, the measured value is not displayed.

TRIG FIN

LVL

fail

MANU

ERR AGE

The Mode Key ( ) was pressed for 3 seconds, which resulted in measurement value display automatic scroll. Manual measurement cannot start during automatic scroll.

The measurement is aborted because the safety function is activated. This function is enabled when the load is turned ON or the insulation resistance is detected extremely low. If the load is not completely stopped, it may be determined that the load is turned ON.

The Main Unit cannot recognize the Probe Unit of this channel. The Units may not be connected properly.

Press the Mode Key ( ) again for 3 seconds to cancel Measurement Value Display Automatic Scroll, and then press the Manual Measurement Key.

Make sure that the load is completely stopped before performing the manual measurement. Also, check the wiring between the load, contactor, and K7GE-MG again.

Check the connection between the Units again.

2-1 Procedure

6 The measurement value is significantly

different from the value measured by the Megohmmeter.

7 The measurement

value is not displayed on the channel, but fail

TRIG FIN LVL

fail

MANU

ERR AGE

is flashing.

It is possible that the manual measurement was performed with the electric charge remaining on the wiring and other parts.

The measurement for this channel is stopped because either the load was turned ON during measurement, or the K7GE-MG detected that the insulation resistance is extremely low.

The Main Unit cannot recognize the Probe Unit of this channel. The Units may not be connected properly.

The manual measurement does not allow forced discharge of electric charge. In the same way as measuring with a Megohmmeter, wait for the charge to be completely discharged before performing manual measurement.

Check again that until the start of automatic measurement, the contactors of all loads turn OFF, and all loads stop completely within the time period of the Motor Stop Waiting Time setting parameter. Also, check the wiring between the load, contactor, and K7GE-MG again.

Check the connection between the Units again.

Insulation Resistance Monitoring Device User’s Manual (N224)

2 - 11

2 Procedure

2 - 12

Insulation Resistance Monitoring Device User’s Manual (N224)

Installation and Wiring

This section describes the installation and wiring of the K7GE-MG device. Before you proceed with installation and wiring, be sure to thoroughly read Precautions for Safe Use on page 6.

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

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 1

3 Installation and Wiring

86 (4)

(1.9)

(Unit: mm)

17.5

(0.9)

(3)

(7.6)

86 (4)

(Unit: mm)

3-1 Dimensions

Main Unit

Probe Unit

3 - 2

Insulation Resistance Monitoring Device User’s Manual (N224)

3-2 Installation

Incorrect

Combining Units

• Remove the right connector cover of the Main Unit and the left connector

cover of the Probe Units.

To prevent dust from entering and failure of the internal circuit due to static electricity, remove the connector covers immediately before connecting the Units.

Remove the right connector cover by using your nail to lift the notch.

3 Installation and Wiring

3-2 Installation

Since the left connector cover is held in place, it may be difficult to remove it simply by pulling up. As shown in the figure, you can easily remove the cover by pushing one of the short sides of the cover and holding up the other short side.

Also, to improve the electrical contact reliability during Unit connection, the pins of the left connector of the Probe Units are kept slightly higher than the height of the case. Be careful when handling as the pins may be damaged if you drop them.

• Join the connectors together.

Make sure that the connectors are connected firmly without any gap between the Units.

(1)

Pins

Protective

ribs

(2)

Make sure to connect the Units before you mount on the DIN Track. If you connect the Units by sliding them on the DIN Track after mounting on the DIN Track, the connectors may be damaged.

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 3

3 Installation and Wiring

(1) (2) (3)

30 mm above

End plate

Downward Vertical

Sidewise Lengthwise

Horizontal

Mounting to DIN Track

• Mounting method

After connecting the Units, pull down all DIN Track mounting hooks on the bottom. Next, hook the upper hook of the K7GE-MG onto the DIN Track and push in the Units. Finally, raise all the DIN Track mounting hooks that were pulled down and fix the K7GE-MG to the DIN Track.

• Dismounting method

Pull out the DIN Track mounting hooks with a flat-blade screwdriver and lift the Unit from the bottom to remove it. Leave at least 30 mm of space between the K7GE-MG and other devices to allow easy installation and removal.

• Install an end plate on the left and right sides.

To prevent a faulty contact between the connectors due to vibrations, mount the Units without any gap so that they are pinched between the end plates. Up to one Main Unit and eight Probe Units can be installed between End Plates.

• Install the K7GE-MG in the horizontal or vertical

direction as much as possible, although there is no restriction on the mounting direction.

• Recommended DIN Track

Model Specifications Manufacturer

PFP-100N 1,000 × 35 × 7.3 mm (L × W × H) OMRON

PFP-50N 500 × 35 × 7.3 mm (L × W × H) OMRON

• Recommended end plates

Model Specifications Manufacturer

PFP-M For PFP-100N/PFP-50N OMRON

3 - 4

Insulation Resistance Monitoring Device User’s Manual (N224)

Replacing the Units

3 Installation and Wiring

• If a Unit is to be replaced due to

a failure, turn OFF the power, remove all wires, and then remove the K7GE-MG from the DIN Track.

Remove temporarily

Replace

3-2 Installation

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 5

3 Installation and Wiring

(3)(2)(1)

(3) (4)(3)(2) (2)(2)(1) (1) (1)

Correct Incorrect Incorrect

MANU

TRIG FIN LVL

ERR AGE

fail

Measurement failed

8888

TRIG FIN

LVL

MANU ERR AGE

System error

Measurement

CH2 and CH3 are out of the scope of measurement

Maximum Number of Channels = 1 (default value)

CH1 CH3CH2

3-3 Setting the Channel Number

Set the channel numbers of the Probe Units.

When setting only one Probe Unit, set the channel number to 1. When setting two or more Probe Units, always set the channel number starting from 1 and then in order such as 2, 3, etc., and n.

Although operation will be performed normally even if the channel numbers are not set in the order of 1, 2, and 3, etc., from the left side, there must not be any missing or duplicate numbers.

If a number is missing in the channel number setting, "measurement failed" occurs when the measurement is performed for the missing channel, and if a number is duplicate, "system error" occurs at the same time when the power is turned ON. Observe that in either case measurement will not be performed normally.

If the number of Probe Units is increased to multiple Units, it is necessary to set the channel number with the Channel Number Setting Switch, and also set the total number of channels (number of Probe Units) in the Maximum Number of Channels setting parameter of the Initial Setting Level. Observe that if you use this setting parameter with the default value, the Probe Units with channel number 2 and later may be out of the scope of measurement.

Refer to 5-3 Maximum Number of Channels on page 5-6 for the operation method of the Maximum Number of Channels setting parameter.

3 - 6

Insulation Resistance Monitoring Device User’s Manual (N224)

3 Installation and Wiring

Terminal (insertion) hole

Release hole

Terminal (insertion) hole

Release hole

3-4 How to Connect to the Push-In Plus

Terminal Blocks

Nomenclature

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

Name Operation

Terminal (insertion) hole Used to insert wires with ferrules, solid wires, and stranded wires.

Release hole Releases the wire when the specified flat-blade screwdriver is inserted.

Also used when inserting stranded wires.

Connecting Wires with Ferrules and Solid Wires

Insert the ferrule or solid wire straight into the terminal block until the end touches the terminal block.

If you use a ferrule with a conductor length of 10 mm, part of the conductor may be visible after the ferrule is inserted into the terminal block, but the product insulation distance will still be satisfied.

If it is difficult to insert fine solid wires, insert the wire with a screwdriver inserted into the release hole, and then remove the screwdriver while ensuring that the fine solid wire is still held.

Terminal (insertion) hole

Ferrule

Release hole

Ferrule

Terminal (insertion) hole

Connecting Stranded Wires

• Hold a flat-blade screwdriver at an angle and

insert it into the release hole. The angle should be between 10° and 15°. If the flat-blade screwdriver is inserted correctly, you will feel the spring in the release hole.

The terminal block may be damaged if you insert the screwdriver with excessive force. Operate the screwdriver with a force of 15 N or less.

• With the flat-blade screwdriver still inserted into

the release hole, insert the wire into the terminal

Insulation Resistance Monitoring Device User’s Manual (N224)

hole until it strikes the terminal block.

• Remove the flat-blade screwdriver from the release hole.

(1)

Flat-blade screwdriver

(2)

Wire

(3)

10° to 15°

(3)

Flat-blade screwdriver

10° to 15°

Flat-blade screwdrive

(1)

Wire

(2)

3 - 7

3 Installation and Wiring

Flat-blade screwdriver

10° to 15°

Flat-blade screwdriver

Wire

(1)

(3)

(2)

Flat-blade screwdriver

Wire

(1)

(3)

(2)

Flat-blade screwdriver

Checking Connection

After the insertion, pull gently on the wire to make sure that it will not come off and the wire is securely fastened to the terminal block.

When you use a stranded wire, make sure the stranded wire does not bend and touch the adjacent terminal.

Removing Wires from the Push-In Plus Terminal Blocks

Use the following procedure to remove wires from the terminal block. The same method is used to remove stranded wires, solid wires, and ferrules.

• Hold a flat-blade screwdriver at an angle and

insert it into the release hole. The angle should be between 10° and 15°. If the flat-blade screwdriver is inserted correctly, you will feel the repellent force of the spring.

• Remove the wire.

• Remove the flat-blade screwdriver from the release hole.

Push-In Plus Terminal Blocks Specifications

 Specifications

Item Specifications

Construction Push-in compatible with 1-pole 2-terminal crossover wiring

Front-in front and front-release Hands-free

Applicable wires Ferrules, solid wires or stranded wires

Applicable wire size

Wire insertion force 8 N max. for AWG 20 wire

0.25 to 1.5 mm

(AWG 24 to AWG 16)

3 - 8

Screwdriver insertion force 15 N max.

Wire stripping length 8 mm*, 10 mm or 12 mm

Ferrule length 8 mm or 10 mm

Current capacity 10 A (per pole)

Number of insertions 50 times

Insulation Resistance Monitoring Device User’s Manual (N224)

* Without ferrules

 Recommended Ferrules

8 to 10 mm

1.9 mm max.

2.6 mm max.

Side

0.4 mm

2.5 mm dia.

2.5 mm

Front

3 Installation and Wiring

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

Applicable wire Ferrule,

Conductor

(mm2)

AWG

length

(mm)

Stripping

length (mm)

(Ferrules

used)

Manufactured by Phoenix Contact

Recommended ferrules

Manufactured by

Weidmuller

Manufactured by

Wago

0.25 24 8 10 AI 0,25-8 H0.25/12 FE-0.25-8N-YE

10 12 AI 0,25-10 - -

0.34 22 8 10 AI 0,34-8 H0.34/12 FE-0.34-8N-TQ

10 12 AI 0,34-10 - -

0.5 20 8 10 AI 0,5-8 H0.5/14 FE-0.5-8N-WH

10 12 AI 0,5-10 H0.5/16 FE-0.5-10N-WH

0.75 18 8 10 AI 0,75-8 H0.75/14 FE-0.75-8N-GY

10 12 AI 0,75-10 H0.75/16 FE-0.75-10N-GY

1/1.25 18/17 8 10 AI 1-8 H1.0/14 FE-1.0-8N-RD

10 12 AI 1-10 H1.0/16 FE-1.0-10N-RD

1.25/1.5 17/16 8 10 AI 1,5-8 H1.5/14 FE-1.5-8N-BK

10 12 AI 1,5-10 H1.5/16 FE-1.5-10N-BK

Recommended crimp tool CRIMPFOX6

PZ6 roto Variocrimp4 CRIMPFOX6T-F CRIMPFOX10S

Note 1. Make sure that the outer diameter of the wire coating is smaller than the inner diameter of the

insulation sleeve of the recommended ferrule.

2. Make sure that the ferrule processing dimensions conform to the figure on the right.

 Recommended Flat-blade Screwdrivers

Model Manufacturer

ESD 0,40×2,5 Wera

SZS 0,4×2,5 SZF 0-0,4×2,5*

0.4×2.5×75 302 Wiha

AEF.2,5×75 FACOM

210-719 Wago

SDI 0.4×2.5×75 Weidmuller

* You can purchase the SZF 0-0,4 × 2,5 flat-blade screwdriver made by PHOENIX CONTACT

with OMRON model XW4Z-00B.

Phoenix Contact

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 9

3 Installation and Wiring

K7GE-MG

Internal 5 V

680 Ω Typ.

Internal ground

K7GE-MG

Approx. 7 mA

External contact

3-5 I/O Wiring

7 NC

17 18

19 20

1 NC

3 NC

Voltage input

Operation power supply

Trigger input

Transistor output

1 2

3 4

5 6

13 14

15 16

Main Unit Probe Unit

Operation Power Supply Terminals

The operation power supply terminals are the No. 1 and No. 2 terminals on the Main Unit. There is no polarity even in the 24 VDC specifications.

3 - 10

Trigger Input Terminals

The specifications of the trigger input terminal are as follows:

Item Specifications

Input type No-voltage contact and open collector are possible.

Residual voltage at short circuit

Open leakage current

ON current at short circuit

In the case of an NPN open collector, the collector is connected to the No. 3 terminal, and the emitter is connected to the No. 4 terminal. Make sure that the values for the residual voltage at short circuit and open leakage current are within the specifications.

The ON current at short circuit is approx. 7 mA. In the case of a no-voltage contact, take note of the drive capacity of micro loads.

1.5 V max.

0.1 mA max.

Approx. 7 mA

Insulation Resistance Monitoring Device User’s Manual (N224)

PE Terminals

3 Installation and Wiring

Earth the PE terminal (No. 7) to the ground. Use AWG 16 for the protective conductor.

When Megger voltage is applied, the measurement current flows from the PE terminal through the insulation resistance of the load, and returns via the L3 terminal (No. 1) of the Probe Unit.

When more than one load is to be measured, perform wiring such that the frame ground of all the loads are earthed to the ground. If there is more than one Main Unit, do not perform crossover wiring for the PE terminals, and earth each PE terminal to the ground. A load that is not earthed to the ground cannot be measured correctly because the path of the measurement current is not established.

Transistor Output Terminals

Megger

voltage

(50 VDC)

K7GE-MG Main Unit

3-5 I/O Wiring

Probe Unit Probe Unit

Item Specifications

Contact form NPN open collector

Rated voltage 24 VDC (maximum voltage: 26.4

VDC)

Maximum current 50 mA

Leakage current

0.1 mA max. when power turning OFF

Residual voltage 1.5 V max.

If the drive capacity is not sufficient, use an

K7GE-MG

To the microcomputer

Functional insulation

ALM 1 output

ALM 2 output

Status output during measurement

Self-diagnosis error output

appropriate relay for relaying.

The specifications of the transistor output terminal are as follows:

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 11

3 Installation and Wiring

2 MΩ Typ.

Voltage monitoring

K7GE-MG

2 MΩ Typ.

Probe Unit

Fuse

Current

limiter

Megger voltage

(50 VDC)

Main Unit

Peak

detection

Note The above diagram shows only the parts of the internal circuit of the

K7GE-MG that are necessary for explanation.

Voltage Input Terminals

Connected between the load wires of the secondary output terminal of the contactor.

The S-phase in a 3-phase system, and the N-phase in a single-phase system is connected to the L2 terminal (No. 3).

The R-phase in a 3-phase system, and the L-phase in a single-phase system is connected to the L3 terminal (No. 1).

Discharge of electric charge and application of the Megger voltage is performed at the L3 terminal.

If the internal circuit components of the K7GE-MG are in a normal state, a current of 3 mA or more will not flow in the L2 and L3 terminals. However, to prevent electric shock accidents due to a short circuit failure of the internal circuit components, be sure to insert a fuse in the L2 and L3 terminals.

Select a fast-blow fuse with a fusing current of 2 A or less, and a rated voltage equal to or more than the line voltage. If a fuse with a fusing current of more than 2 A is used, ensure that the wire connected to the PE terminal has a diameter that allows a sufficient flow of the fusing current.

3 - 12

Insulation Resistance Monitoring Device User’s Manual (N224)

3 Installation and Wiring

USB

K7GE-MG

Main Unit

(+)6(-)

K7GE-MG

Main Unit

(+)6(-)

K7GE-MG

Main Unit

(+)6(-)

(+) (-)

Terminating resistance

500 m max.

Up to 32 Units (including the host system)

120 Ω 1/2 W

Terminating resistance

120 Ω 1/2 W

Communications converter

RS-485 USB

3-6 Wiring the Communications Cable

When you use the communications function, wire a communications cable.

Connect (+) to the No. 5 terminal and (-) to the No. 6 terminal on the Main Unit. Crossover wiring is possible as this is a Push-In Plus terminal block.

The connection configuration of Master:Slave is 1:1 or 1:N. In the case of the 1:N connection configuration, you can connect up to 32 Units including the host system that is the master.

The total cable length is 500 m max.

3-6 Wiring the Communications Cable

Install a terminating resistance of 120 Ω, 1/2 W on both ends of the transmission path. Use a twisted-pair cable (AWG 24 to AWG 16) as the cable.

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 13

3 Installation and Wiring

No. 01 No. 02 No. 02

Master

No. 01 No. 02 No. 02

Master

Command to No. 2

Response from No. 2

Incorrect

3-7 Setting the Unit Number

When you use the communications function, set a unit number for the Main Unit.

You can set a number from 00 to 99. The power ON reset process (Reset Key operation or turning the power ON again) is required. Make the settings when the power is OFF.

Up to one master host system and 31 slave Main Units can be connected on the same communications. The unit number is used to distinguish between slaves.

If Modbus RTU is selected as the protocol, use a unit number between 01 and 99. If you communicate with the slave with unit number 00, slave address 00 will be broadcast in the Modbus RTU protocol. However, the K7GE-MG does not support broadcasting.

The master executes a command by specifying the unit number in the communications command. Therefore, the slaves connected on the same communications line must not have duplicate unit numbers. If the unit number is duplicated, there will be a clash between the responses from multiple slaves, which will result in a communications error.

3 - 14

Insulation Resistance Monitoring Device User’s Manual (N224)

3 Installation and Wiring

3-8 Connecting to a Load or Contactor

The following describes how to connect the K7GE-MG with a load or contactor.

When the Load Is a Single-phase/3-phase Induction Motor (Direct Connection to Commercial Power Supply)

Install a contactor between the power line and the motor.

Do not connect any other device such as a transformer or a filter between the contactor and the motor. Doing so may cause incorrect measurement.

Connect the voltage input of the Probe Unit of the K7GE-MG to the secondary output terminal (motor side) of the contactor.

Make sure that it is not connected to the primary side (power supply side). It cannot be measured correctly and may cause a hazardous condition.

RS T

Contactor

MC-a

Operation

power supply

Status output during measurement

17 18

Trigger

input

1 33 4

Probe Unit

Main Unit

13 14 15 16

K7GE-MG

ALM 1 ALM 2

3-8 Connecting to a Load or Contactor

The figure shows a simplified view of the wiring for status output during measurement, and ALM 1 and ALM 2 outputs. Use an appropriate relay for relaying in consideration of the switching capacity of the output transistor. The specifications of the output transistor for the K7GE-MG are 24 VDC (+10%), 50 mA max.

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 15

3 Installation and Wiring

MC-a

17 18 13 14 15 16

Trigger

input

Operation

power supply

Status output during measurement

ALM 1 ALM 2

17 18

1 33 4

Probe Unit

K7GE-MG

Contactor

RST

UVW

Inverter

Output noise filter

Main Unit

When the Load Is an Inverter-driven Motor

Install a contactor between the inverter output and the motor.

If a noise filter is to be inserted at the output side of the inverter, insert it between the inverter output and the primary output terminal of the contactor.

Do not connect any other device such as a transformer or a filter between the contactor and the motor. Doing so may cause incorrect measurement.

Connect the voltage input of the Probe Unit of the K7GE-MG to the secondary output terminal (motor side) of the contactor.

Make sure that it is not connected to the primary side (power supply side). It cannot be measured correctly and may cause a hazardous condition.

3 - 16

Insulation Resistance Monitoring Device User’s Manual (N224)

3 Installation and Wiring

Do not connect any other device such as a transformer or a filter between the contactor and the motor. Doing so may cause incorrect measurement.

Make sure that it is not connected to the primary side (power supply side). It cannot be measured correctly and may cause a hazardous condition.

If the contactor is turned OFF while the Servo Drive is turned ON, the rotating shaft of the motor will be in a free. If the contactor is turned on after that, the motor may perform unintended operation and can be dangerous.

MC-a

17 18

13 14 15 16

Main Unit

Trigger

input

Operation

power supply

Status output during measurement

ALM 1 ALM 2

17 18

1 33 4

Probe Unit

K7GE-MG

Contactor

TSR

UVW

Servo Drive

Relay

Brake cable

Brake

Contactor

OFF

Contactor

OFF

Servo

motor

Servo Drive

power supply

Servo Drive

power supply

Motor power

cable

Incorrect

Correct

When the Load Is a Servo Motor

Install a contactor between the Servo Drive output and the motor.

The contactor is required only in the power line. Relays the motor power cables other than the power line to the terminal blocks and connect it to the Servo Drive directly.

Connect the voltage input of the Probe Unit of the K7GE-MG to the secondary output terminal (motor side) of the contactor.

Turn the contactor ON and OFF when the Servo Drive power is OFF.

3-8 Connecting to a Load or Contactor

Insulation Resistance Monitoring Device User’s Manual (N224)

3 - 17

3 Installation and Wiring

3 - 18

Insulation Resistance Monitoring Device User’s Manual (N224)

Functions Related to Measurement

This section describes automatic measurement and manual measurement of the K7GE-MG, as well as the 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

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

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 1

4 Functions Related to Measurement

MC-a

External contact

K7GE-MG

Trigger signal

(to the microcomputer)

Trigger input terminal

Trigger input circuit (conceptual diagram)

Trigger Signal Reverse

setting parameter

External

contact

Trigger Signal Reverse

setting parameter

Trigger

signal

OFF OFF (default value) ON

ON OFF

ON OFF (default value) OFF

ON ON

4-1 Automatic Measurement

The K7GE-MG normally operates with automatic measurement. Automatic measurement is performed in synchronization with the trigger signal. The following describes the operation of automatic measurement.

4-1-1 Trigger Input

Trigger by an External Contact

The K7GE supports connecting the auxiliary contact of the contactor that turns the power of the load ON or OFF to the trigger input terminal. In addition, it also supports control using the I/O ports of the PLC, and the signal logic can be reversed with the setting parameters.

Therefore, "trigger input ON" cannot simply distinguish whether the trigger signal is an external contact or a measurement start signal.

Thus, in this manual, trigger signal ON means enabled (measurement start signal is enabled) and trigger signal OFF means disabled.

The table on the right shows the relationship between the external contact, Trigger Signal Reverse setting parameter, and trigger signal connected to the trigger input terminal. The auxiliary contact of the contactor is used as the measurement start signal. The initial value of the setting parameter is set so that the trigger signal is turned ON (enabled) when the external contact is turned OFF (contactor is turned OFF).

Observe that this manual describes the measurement start signal as a trigger signal rather than an external contact, such as a time chart description.

4 - 2

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

Trigger signal

External contact

OFF

Trigger signal

Communications

command

Trigger by a Communications Command

Automatic measurement can be started by giving a trigger signal to the K7GE-MG from a communications command as well as an external contact. However, the operation is slightly different from that of an external contact. To keep the trigger signal ON, the external contacts must be kept OFF*. However, in the case of the communications command, the trigger signal is kept ON with a one-shot command.

* When the setting value of the Trigger Signal Reverse setting parameter changes to OFF.

Overlapping between the timing of the trigger by an external contact and the trigger by a communications command is a post-win. For example, if the measurement operation starts by an external contact and a communications command is input before the measurement operation completes, the measurement started by the external contact is reset, and a new measurement operation by the communications command starts.

4-1 Automatic Measurement

We recommend using either external contact or communications command, as the operation is difficult to see from the outside.

4-1-1 Trigger Input

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 3

4 Functions Related to Measurement

Note If the trigger input is a

communications command, TRIG indicator will not light.

Trigger signal

Measurement operation

Motor stop

standby

Waiting for

stability

Sampling

CH1

CH2 CH3

Discharge of

electric charge

TRIG FIN

MC-a

Measurement start signal

Measurement starts at auxiliary contact OFF

4-1-2 Measurement Steps

Automatic measurement consists of four steps.

Motor stop standby Discharge of electric charge

Automatic measurement is started with trigger signal

Step: Motor stop standby

Step:

Waiting for stability Sampling

Step: Waiting for stability

Step: Sampling

Automatic measurement is ended

Even when measuring multiple channels, the motor stop standby step is performed only once at the beginning of the measurement operation. Other than that, the steps are executed each time measurement is performed for each channel.

Discharge of electric charge

Measurement

completed for all

channels

TRIG FIN

4 - 4

The time required for automatic measurement changes depending on the setting values of the setting parameters. However, if the setting parameters are set to the default values, the time required for automatic measurement is approx. 91 seconds in the minimum configuration of one Probe Unit, and approx. 658 seconds in the maximum configuration of eight Probe Units.

Motor Stop Standby

If the auxiliary contact of the contactor that turns ON/OFF the power of the load is connected to the trigger input terminal, the trigger signal for measurement start can be easily created. However, since the auxiliary contact is linked to the contactor, the trigger signal turns ON at the time when the contactor turns OFF*.

* When the setting value of the Trigger Signal Reverse setting parameter

changes to OFF.

If the load is a motor, it does not stop immediately when it is disconnected from the power, but stops gradually in due course of time by slowing down. A line voltage is generated during the time the motor is rotating. Therefore, even if the trigger signal turns ON, it is necessary to wait for the measurement to stop completely.

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

TRIG FIN

Note The above diagram shows only the parts

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

TRIG FIN

Note The above diagram shows only the parts

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

The first step of automatic measurement is to wait for the time until the motor stops completely.

The time until the stop of the motor varies depending on the size of the motor and the inertia of the equipment being driven. Therefore, the waiting time can be adjusted by the Motor Stop Waiting Time setting parameter (0 to 299 seconds).

Refer to 5-7 Motor Stop Waiting Time on page 5-15 for the operation method of the Motor Stop Waiting Time setting parameter.

Discharge of Electric Charge

A parasitic capacitance component is present between the load including the wiring from the contactor and the ground. Therefore, even if the contactor is turned OFF, the electric charge accumulated in the capacity component is not discharged immediately. It would take several minutes for the electric charge to be discharged naturally, so this step forcibly discharges the charge.

Contactor

Trigger signal

Motor speed

Measurement

Rz Cz

OFF

Complete stop

Motor stop

standby time

K7GE-MG

S1 S2

Discharge

of electric

charge

CH1

Apply

Megger

voltage

4-1 Automatic Measurement

4-1-2 Measurement Steps

The time for this step is fixed as 20 seconds.

Waiting for Stability

In this step, the application of the Megger voltage starts, but due to the parasitic capacitance component, it may take some time for the measurement value to reach the final value. In this step, the K7GE-MG waits for a fixed period of time with the Megger voltage still applied in order to adopt the stable final value as the measurement value.

The time until the value becomes stable varies depending on the status of the equipment and wiring. Therefore, the waiting time can be adjusted by the Time to Wait to Stabilize setting parameter (0 to 99 seconds).

Refer to 5-8 Time to Wait to Stabilize on page 5-17 for the operation method of the Time to Wait to Stabilize setting parameter.

Rz Cz

K7GE-MG

S1 S2

Discharge

of electric

charge

Apply

Megger

voltage

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 5

4 Functions Related to Measurement

Sampling

Measurement value

Waiting for stability

Measurement

Measurement value

0.8 s or 6.4 s

Alarm judgment

ON/OFF

Alarm output

Measurement value confirmation

TRIG FIN

Trigger signal

Motor stop

standby

Measurement operation

Discharge of

electric charge

Discharge of

electric charge

Waiting for

stability

Sampling

CH3

Measurement end

indicator is lit

FIN

Sampling

TRIG FIN

In this step, the measurement value is confirmed, and an alarm judgment is performed.

Depending on whether or not average processing is performed for the measurement values, the time taken for this step is 0.8 seconds or 6.4 seconds.

Whether or not to perform average processing can be set by the Average Processing setting parameter. Refer to 5-9 Average Processing on page 5-19 for the operation method.

The alarm judgment is performed based on the confirmed measurement value, and an alarm is output.

The threshold value used in the alarm judgment can be set by the Alarm Value 1 and Alarm Value 2 setting parameters. Refer to 5-4 Alarm Values 1 and 2 on page 5-9 for the operation method.

If there is another channel to measure, the measurement is performed from the second step "Discharge of electric charge".

Automatic Measurement Is Ended

This is the state when automatic measurement of all channels is complete.

FIN indicator is lit on the measurement step indicator.

4 - 6

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

External

contact

OFF

Trigger

signal

Measurement

operation

CH1

Discharge of

electric charge

Waiting for stability

Sampling

CH2 CH3

(1) (2) (3) (4) (5) (6) (7)

Motor stop standby

TRIG FIN TRIG FIN TRIG FIN TRIG FIN TRIG FIN TRIG FIN TRIG FIN

4-1-3 Measurement Step Indicator Operation

The relationship between the progress of the steps and the measurement step indicator is described with an example in which three Probe Units are connected.

(1) The trigger signal turns ON when the external contact changes from ON to OFF*, and the

measurement operation starts. The first step of the measurement operation is motor stop standby.

* When the setting value of the Trigger Signal Reverse setting parameter is OFF

Linking to the external contact occurs and TRIG indicator is lit on the measurement step indicator. (If the trigger signal is from a communications command, TRIG indicator is not lit.)

(2) The processing shifts to the discharge of electric charge step of channel 1.

The first arrow of the measurement step indicator is lit to indicate that the discharge of electric charge is in progress.

4-1 Automatic Measurement

4-1-3 Measurement Step Indicator Operation

(3) The processing shifts to the waiting for stability step.

Megger voltage is applied to the load of channel 1, and the K7GE-MG waits for a fixed period of time. The second arrow of the measurement step indicator is lit to indicate that the K7GE-MG is waiting for stability.

(4) The processing shifts to the sampling step.

The measurement values are read. The third arrow of the measurement step indicator is lit to indicate that sampling is in progress. The alarm judgment is performed based on the confirmed measurement value, and an alarm is output.

(5) The measurement operation shifts to channel 2.

For channel 2, the processing starts from the discharge of electric charge step.

(6) The series of measurement operations ends.

FIN indicator is lit on the measurement step indicator to indicate the end of the measurement operation.

(7) Since the measurement step indicator TRIG is linked to the external contact, it turns OFF when the

external contact turns ON. Even when TRIG indicator is not lit, the confirmed measurement values are retained. This state continues until automatic measurement starts again with the next trigger signal ON, or measurement standby occurs as a result of reset.

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 7

4 Functions Related to Measurement

MC-a

Trigger input

(3)(1) (2)

+CH3

C/D

CH3

Results

display

+CH3

CH2CH3

CH1CH2

CH2

trig

OFF

(3)

(4)

)

Measureme

end

(7)

stop

(6)

CH2CH2

OFF

CH3

MEAS

MANU

LVL

ERR AGE

----

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

TRIG FIN

MEAS

MANU

TRIG FIN LVL

ERR AGE

--91

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

4-1-4 Timing Charts

Timing Charts for Measurement Start/End/Stop

The relationship between the timing of measurement start, end, and stop during automatic measurement by a trigger signal, and each display and contact output is described using a specific example.

The configuration and initial settings are as follows:

• Connect the contactor auxiliary contact of the load to the trigger input

terminal

• Connect three Probe Units

• The channel number setting of each Unit is channel 1, 2, and 3 from the left

• Set the setting value of the Maximum Number of Channels setting parameter

to 3

• Set the setting value of the Trigger Signal Reverse setting parameter to OFF

OFF

----

(1)

Motor stop

standby

Countdown

CH1

(2)

Start automatic

measurement

CH1

CH2 CH3

CH1MEAS indicator CH2

CH1

C/D

CH2

(3) (4)

OFF

CH3 CH1

+CH2

C/D CH3

+CH3

Results

display

(5)

Measurement end

Power supply

External contact

Trigger signal

Measurement operation

Status output during

measurement

ALM 1, ALM 2 output

Alarm output indicator

ALM indicator

Main display

(1) Power ON

Even if the external contact is already OFF when the K7GE-MG power is turned ON, enabled trigger signals are not accepted.

---- is displayed on the main display part, indicating measurement standby.

(6)

Motor stop

otor stop

standby

OFF

Countdown

ountdow

CH1

CH1 CH2

CH2

CH1

C/D CH2

OFF

+CH2 ON

trig

(7)

Measurement

easurement

stop

H2 ON

CH2

flashes

flash

4 - 8

(2) Start automatic measurement

The trigger signal turns ON when the external contact changes from ON to OFF, and automatic measurement starts. The following parts operate simultaneously with the start of automatic measurement.

• Status output during measurement turns ON

• TRIG indicator is lit on the measurement step indicator

• The countdown until the measurement completes for channel 1 is displayed on the main display part

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

Power supply

External contact

OFF

Trigger signal

Motor stop

standby

Measurement operation

Status output during

measurement

CH1

ALM 1, ALM 2 output

CH1

Alarm output indicator

CH1

ALM indicator

Countdown

CH1

Main display

----

CH2 CH3

+CH2

+CH3

C/D

CH2

C/D CH3

Results

display

+CH3

OFF

Motor stop

standby

CH1 CH2

Countdown

CH1

C/D CH2

CH1

+CH2 ON

CH2

trig

flashes

OFF

(1) (2)

Start automatic measurement

(3) (4)

(5)

Measurement end

(7)

Measurement stop

(6)

CH1MEAS indicator CH2

OFF

CH2

OFF

CH3 CH1

OFF

+CH3

Results

display

+CH3

CH1CH2

CH2

OFF

)

Measureme

end

(7)

stop

(6)

CH2

OFF

(1)

(2)

easureme

(

OFF

Measurement is performed for channel 1 after motor stop standby. When measurement starts, the MEAS indicator on the Probe Unit of channel 1 turns ON, which indicates that measurement is in progress.

TRIG FIN LVL

--81

MANU

ERR AGE

ALM 2

ALM 1

MEAS

ALM

CH1

MEAS

ALM

CH2

MEAS

ALM

CH3

4-1 Automatic Measurement

---

otor stop standby

tart automatic

ountdown

(3) Measurement moves from channel 1 to channel 2

The following parts operate simultaneously with the confirmation of the measurement value for channel 1.

• The results of alarm judgment for CH1 are reflected in ALM 1/ALM 2 output

• The results of alarm judgment for CH1 are reflected in the alarm output indicator

• The results of alarm judgment for CH1 are reflected in the ALM indicator of the Probe Unit

• The MEAS indicator of CH1 is not lit and the MEAS indicator of CH2 is lit

• The countdown until the measurement completes for channel 2 is displayed on the main display part

otor stop

tandby

ountdown

H2 ON

flash

easurement

MEAS

ALM

CH2

MEAS

ALM

CH3

TRIG FIN LVL

-- 81

MANU

ERR AGE

ALM 2

ALM 1

The above display example shows a case in which no alarm occurs for channel 1.

Alarm output indicator: Green ALM indicator: Not lit ALM 1 output: OFF

MEAS

ALM

CH1

4-1-4 Timing Charts

Insulation Resistance Monitoring Device User’s Manual (N224)

(4) Measurement moves from channel 2 to channel 3

The following parts operate simultaneously with the confirmation of the measurement value for channel 2.

• The results of alarm judgment for CH2 are reflected in ALM 1/ALM 2 output*

• The results of alarm judgment for CH2 are reflected in the alarm output indicator*

• The results of alarm judgment for CH2 are reflected in the ALM indicator of the Probe Unit

• The MEAS indicator of CH2 is not lit and the MEAS indicator of CH3 is lit

• The countdown until the measurement completes for channel 3 is displayed on the main display part

* The parameters that are turned ON in the judgment results for CH1 will not turn OFF.

MEAS

ALM

CH2

MEAS

ALM

CH3

TRIG FIN LVL

--81

MANU

ERR AGE

ALM 2

ALM 1

The above display example shows a case in which an alarm (warning) occurs for channel 2.

Alarm output indicator: Yellow ALM indicator: Lit ALM 1 output: ON

ALM

CH1

4 - 9

4 Functions Related to Measurement

CH1CH2

CH2

OFF

(7)

stop

)

CH2

OFF

CH2C

C/D

OFF

(1)

(2)

easureme

(3)

(4)

CH1C

OFF

MEAS

TRIG FIN

LVL

ERR AGE

--!5

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

MEAS

TRIG FIN

LVL

--!5

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

MANU

The above display example shows a case in which an alarm (critical) occurs for channel 3.

Alarm output indicator: Red CH3 ALM indicator: Lit ALM 1 output: ON ALM 2 output: ON

FIN

MANU

TRIG LVL

ERR AGE

-9&8

FIN

MANU

TRIG LVL

ERR AGE

-1%3

FIN

MANU

TRIG LVL

ERR AGE

-9!5

OFF

Power supply

External contact

Trigger signal

Motor stop

OFF

----

---

otor stop

standby

tandby

Start automatic

tart automatic

measurement

CH1

CH1MEAS indicator CH2

Countdown

ountdown

CH1

CH2 CH3

CH1

C/D

CH2

(3) (4)

OFF

CH3 CH1

+CH2

C/D CH3

(5)

+CH3

Results

display

Measurement end

Measurement operation

Status output during

measurement

ALM 1, ALM 2 output

Alarm output indicator

ALM indicator

Main display

(1) (2)

(5) Measurement end

The following parts operate simultaneously with the confirmation of the measurement value for channel 3.

• Status output during measurement turns OFF

• The results of alarm judgment for CH3 are reflected in ALM 1/ALM 2 output*

• The results of alarm judgment for CH3 are reflected in the alarm output indicator*

• The results of alarm judgment for CH3 are reflected in the ALM indicator of the Probe Unit

• The MEAS indicator of CH3 is not lit

Motor stop

otor stop

standby

OFF

(6)

CH1 CH2

Countdown

ountdown

CH1

CH2

CH1

C/D CH2

(7)

OFF

+CH2 ON

H2 ON

+CH2 ON

H2 ON

+CH2 ON

H2 ON

CH2

trig

flashes

flash

Measurement

easurement

stop

* The parameters that are turned ON in the judgment results for CH1 and CH2

will not turn OFF.

Since there are three Probe Units, the measurement operation ends when the measurement for channel 3 ends.

The measurement results of channel 3 are displayed on the main display part. The measurement results of channel 1 to 3 can be

referenced with the Mode Key ( ).

4 - 10

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

----

Power supply

External contact

OFF

Trigger signal

Motor stop

standby

Measurement operation

Status output during

measurement

CH1

ALM 1, ALM 2 output

CH1

Alarm output indicator

CH1

ALM indicator

Countdown

CH1

Main display

CH2 CH3

+CH2

+CH3

C/D

CH2

C/D CH3

Results

display

+CH3

OFF

Motor stop

standby

CH1 CH2

Countdown

CH1

C/D CH2

CH1

+CH2 ON

CH2

trig

flashes

OFF

(1) (2)

Start automatic measurement

(3) (4)

(5)

Measurement end

(7)

Measurement stop

(6)

CH1MEAS indicator CH2

OFF

CH2

OFF

CH3 CH1

OFF

CH1C

CH2CH3+C

+CH3

C/D

CH3

Results

display

+CH3

OFF

(1)

(2)

easureme

(3)

(4)(5)

Measureme

end

CH1C

OFF

CH3

MEAS

MANU

TRIG FIN LVL

ERR AGE

--91

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

MEAS

MANU

LVL

ERR AGE

trig

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

TRIG FIN

Insulation Resistance Monitoring Device User’s Manual (N224)

(6) Restart automatic measurement

Here, in order to explain the operation of (7) Measurement stop, the measurement is restarted by a trigger signal that changes the external contact from ON to OFF. The previous measurement values, ALM 1/ALM 2 output, alarm output indicator, and the ALM indicator of the Probe Unit are all cleared (turned OFF).

(7) Measurement stop

Here, the operation when the external contact turns ON (the trigger signal is OFF) during the measurement for channel 2 is described. In such a case, the measurement operation stops. The following parts operate simultaneously with the stop of measurement.

• Status output during measurement turns OFF

• Linking to the external contact occurs and TRIG turns OFF on the measurement step indicator

• trig flashes on the main display part, indicating the stop of measurement due to trigger signal OFF

• ALM 1 output and ALM 2 output turn ON*

• The alarm output indicator is lit red*

• The ALM indicator of the CH2 Probe Unit is lit*

* Since the measurement value of channel 2 cannot be identified when

measurement is stopped, the measurement value is treated as 0 MΩ internally, and alarm judgment is performed.

If you display the measurement results using the Mode Key ( ), the measurement value is displayed for channel 1 and trig flashes for channel 2. Also, ---- is displayed for channel 3 to indicate measurement standby.

otor stop standby

---

tart automatic

ountdown

+CH2

TRIG

LVL

-9&8

MANU

ERR AGE

TRIG FIN

LVL

trig

MANU

ERR AGE

LVL

----

MANU

ERR AGE

4 - 11

4-1 Automatic Measurement

4-1-4 Timing Charts

FIN

FINTRIG

4 Functions Related to Measurement

Trigger input

PLC

(3)(1) (2)

Load (motor) CH3

OFF

PLC contact

Trigger signal

Motor stop

standby

Measurement operation

Status output during

measurement

CH1ALM 1, ALM 2 output

CH1Alarm output indicator

CH1ALM indicator

Countdown

CH1

Main display

----

CH2

ALM 1, ALM 2 ON

C/D

CH2

C/D CH3

+CH3

OFF

CH1

Countdown

CH1

CH2

fail

flashes

OFF

(1) (2) (3)

Measurement failed

(4) (5)

Load (motor) CH2

OFF

Load (motor) CH1

OFF

CH1 CH3

Lit red

+CH2 ON

CH1MEAS indicator

OFF

CH1

OFF

CH2 CH3

Motor stop

standby

CH2

C/D

CH3

OFF

(2)(3

)

Measureme

(4)(5)

CH2CH1

CH3

OFF

CH1

CH2CH3

MEAS

MANU

TRIG FIN LVL

ERR AGE

--91

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

MEAS

MANU

TRIG FIN LVL

ERR AGE

--81

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

Timing Chart for Measurement Failure

The operation when measurement fails during automatic measurement is described using a specific example. The configuration and initial settings are as follows:

• Connect the output contact of the PLC to the

trigger input terminal

• Connect three Probe Units

• The channel number setting of each Unit is

channel 1, 2, and 3 from the left

• Set the setting value of the Maximum Number

of Channels setting parameter to 3

• Set the setting value of the Trigger Signal Reverse setting parameter to ON

4 - 12

(1) Start automatic measurement

The trigger signal turns ON when the PLC contact changes from OFF to ON*, and measurement starts.

* When the setting value of the Trigger Signal Reverse setting parameter is ON

The following parts operate simultaneously with the start of automatic measurement.

• Status output during measurement turns ON

• TRIG indicator is lit on the measurement step indicator

• The countdown until the measurement completes for channel 1 is displayed on the main display part

Measurement is performed for channel 1 after motor stop standby. When measurement starts, the MEAS indicator on the Probe Unit of channel 1 turns ON, which indicates that measurement is in progress.

otor stop

tandby

Insulation Resistance Monitoring Device User’s Manual (N224)

+CH2 ON

fail

LM 1, ALM 2 ON

t r

+CH

ail

flash

ountdown

4 Functions Related to Measurement

OFF

Trigger signal

Motor stop

standby

Measurement operation

Status output during

measurement

CH1ALM 1, ALM 2 output

CH1

Alarm output indicator

CH1ALM indicator

Countdown

CH1

Main display

----

CH2

ALM 1, ALM 2 ON

C/D CH2

C/D

CH3

+CH3

OFF

CH1

Countdown

CH1

CH2

fail flashes

OFF

(1) (2) (3)

Measurement failed

(4) (5)

OFF

CH1 CH3

Lit red

+CH2 ON

CH1MEAS indicator

OFF

CH1

OFF

CH2 CH3

Motor stop

standby

CH1C

CH1

OFF

(4)(5)

OFF

)

OFF

CH1

OFF

Load (motor) CH3

Load (motor) CH2

Load (motor) CH1

PLC contact

otor stop

tandby

---

ountdow

(2) Measurement moves from channel 1 to channel 2

The following parts operate simultaneously with the confirmation of the measurement value for channel 1.

• The results of alarm judgment for CH1 are reflected in ALM 1/ALM 2 output

• The results of alarm judgment for CH1 are reflected in the alarm output indicator

• The results of alarm judgment for CH1 are reflected in the ALM indicator of the Probe Unit

• The MEAS indicator of CH1 is not lit and the MEAS indicator of CH2 is lit

• The countdown until the measurement completes for channel 2 is displayed on the main display part

1, ALM 2 ON

t r

+CH

ailflash

otor stop

tandby

ountdow

MEAS

ALM

CH2

MEAS

ALM

CH3

TRIG FIN LVL

--81

MANU

ERR AGE

ALM 2

ALM 1

The above display example shows a case in which no alarm occurs for channel 1.

Alarm output indicator: Green ALM indicator: Not lit ALM 1 output: OFF

MEAS

ALM

CH1

4-1 Automatic Measurement

4-1-4 Timing Charts

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 13

4 Functions Related to Measurement

MEAS

MANU

TRIG FIN LVL

ERR AGE

--81

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

(3) Measurement failed

Here, the operation when the loads of channel 1 and 2 restart unintentionally during the measurement for channel 2 is described. In such a case, the safety function activates, the measurement operation of channel 2 stops, and the measurement moves to the next channel 3. The following parts operate simultaneously with the failure of measurement.

• The countdown until the measurement completes for channel 3 is displayed on the main display part

• ALM 1 output and ALM 2 output turn ON*

• The alarm output indicator is lit red*

• The ALM indicator of the CH2 Probe Unit is lit*

• The MEAS indicator of CH2 is not lit and the MEAS indicator of CH3 is lit

* Since the measurement value of channel 2 cannot be identified when the

measurement fails, the measurement value is treated as 0 MΩ internally, and alarm judgment is performed. Although channel 1 is restarted, the measurement is already complete. Therefore, there is no change in the alarm judgment and the measurement value.

4 - 14

Insulation Resistance Monitoring Device User’s Manual (N224)

OFF

Trigger signal

Motor stop

standby

Measurement operation

Status output during

measurement

CH1

ALM 1, ALM 2 output

Alarm output indicator

CH1

CH1ALM indicator

Countdown

CH1

Main display

----

CH2

ALM 1, ALM 2 ON

C/D CH2

C/D

CH3

+CH3

OFF

Motor stop

standby

CH1

Countdown

CH1

CH2

failflashes

OFF

(1) (2) (3)

Measurement failed

(4) (5)

OFF

CH1 CH3

Lit red

+CH2 ON

CH1MEAS indicator

OFF

CH1

OFF

CH2 CH3

OFF

CH1

CH2

C/D

CH2

OFF

(1)(2)(3

)

Measureme

OFF

CH1

CH3

CH1

OFF

CH2

CH3

Load (motor) CH3

Load (motor) CH2

Load (motor) CH1

PLC contact

MEAS

TRIG FIN

LVL

ERR AGE

--!5

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

MEAS

TRIG FIN

LVL

--!5

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

MANU

The above display example shows a case in which an alarm (critical) occurs for channel 3.

CH3 ALM indicator: Lit Shown as follows due to measurement failure of channel 2

Alarm output indicator: Red

CH3 ALM indicator: Lit

ALM 1 output: ON

ALM 2 output: ON

FIN

MANU

TRIG LVL

ERR AGE

-9&8

FIN

MANU

TRIG LVL

ERR AGE

-9!5

MANU

LVL

ERR AGE

fail

TRIG FIN

4 Functions Related to Measurement

otor stop

tandby

H2 ON

---

ountdown

fail

(4) Measurement end

The following parts operate simultaneously with the confirmation of the measurement value for channel 3.

• Status output during measurement turns OFF

• The results of alarm judgment for CH3 are reflected in the ALM indicator of the Probe Unit

• The MEAS indicator of CH3 turns OFF

The alarm-related output/display due to measurement failure of channel 2 are as follows:

• ALM 1/ALM 2 output are in the ON state

• The alarm output indicator turns red to indicate a critical alarm

4-1 Automatic Measurement

4-1-4 Timing Charts

Since there are three Probe Units, the measurement operation ends when the measurement for channel 3 ends.

The measurement results of channel 3 are displayed on the main display part. If the measurement results are referenced with the

Mode Key ( ), the measurement values are displayed for channel 1 and channel 3, and fail flashes for channel 2 to indicate "measurement failed".

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 15

4 Functions Related to Measurement

MEAS

MANU

TRIG FIN LVL

ERR AGE

--91

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

FIN

MANU

TRIG LVL

ERR AGE

-9&8

FIN

MANU

TRIG LVL

ERR AGE

-1%3

FIN

MANU

TRIG LVL

ERR AGE

-9!5

Manual scroll

MANU

TRIG LVL

ERR AGE

9&8

At least

1 second

FIN

MANU

TRIG

LVL

ERR AGE

-9&8

FIN

MANU

TRIG

LVL

ERR AGE

-1%3

FIN

MANU

TRIG

LVL

ERR AGE

-9!5

Automatic scroll

At least 3 seconds

Press and hold for at least 2 seconds

5 seconds elapsed

Automatic scroll stopped in the pressed channel

When the key is released

Power supply

Measurement

operation

M Key

Manual

Measurement

value display

scroll

At least 3 seconds

Automatic

(5) Restart automatic measurement

The trigger signal turns ON when the PLC contact changes from OFF to ON, and measurement starts again. Status output during measurement turns ON simultaneously with measurement start. The previous measurement values, ALM 1 and ALM 2 outputs, ALM indicator of the Probe Unit, and the alarm output indicator are all cleared (turned OFF) simultaneously with measurement start.

4-1-5 Measurement Value Display Automatic Scroll

If you press the Mode Key ( ) when the measurement values are confirmed, the measurement values for each channel are displayed sequentially each time

the Mode Key ( ) is pressed (manual scroll).

4 - 16

If you press the Mode Key ( ) for at least 3 seconds, the display moves automatically every 5 seconds even without pressing the key each time (automatic scroll).

Press the Mode Key ( ) again for at least 3 seconds during automatic scroll to return to manual scroll.

During automatic scroll, the measurement results of multiple channels can be checked without operating the keys. Therefore, it can be conveniently used when checking the measurement values of multiple systems and multiple channels such as during patrolling.

If automatic scroll display is set, the automatic scroll continues until the operation for canceling

automatic scroll by the Mode Key ( ) is performed. It also continues when the power is turned ON again.

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

Automatic measurement

Trigger

signal

Measurement

operation

Measurement

value

Manual measurement

Input value

Sampling

Measurement value

Start

Manual measurement

4-2 Manual Measurement

K7GE-MG is basically used in automatic measurement in synchronization with the trigger signal. In addition, K7GE-MG is also equipped with a manual measurement function which corresponds to a Megohmmeter. Manual measurement does not require a trigger signal and can be started manually and measured continuously. Therefore, it can be conveniently used at system startup and maintenance.

Differences from Automatic Measurement

The measurement operation during manual measurement does not have multiple measurement steps as in automatic measurement, and sampling is continuously performed right from the time monitoring is started.

4-2 Manual Measurement

The differences from automatic measurement are

as follows:

Automatic

measurement

Time of use Normal operation When starting the

Measurement operation

Measurement steps

Alarm judgment Ye s N o

Alarm output Ye s No

Average processing of measurement values

Manual measurement does not have the discharge of electric charge step. Start the K7GE-MG when the electric charge has been sufficiently discharged. If the K7GE-MG is started when some electric charge is remaining, measurement cannot be performed correctly.

Synchronous with the trigger signal

Motor stop standby/Discharge of electric charge/Waiting for stability/Sampling

Supported Supported

Manual

measurement

system, during maintenance

Continuous monitoring

None The measurement step indicator is also not required

Insulation Resistance Monitoring Device User’s Manual (N224)

Alarm judgment is not performed during manual measurement. Also, all confirmed measurement values, alarm outputs, etc. are cleared when manual measurement is started. Use it with caution.

The setting value of the Average Processing setting parameter is enabled even in manual measurement. When you perform the Average Processing setting parameter on the measurement values, the display refresh period is approximately 0.8 seconds or 6.4 seconds. Refer to 5-9 Average Processing on page 5-19 for the operation method of the Average Processing setting parameter.

4 - 17

4 Functions Related to Measurement

Power ON reset

Operation Level

Power ON

----

TRIG FIN

LVL

MANU ERR AGE

FIN

MANU

TRIG

LVL

ERR AGE

-9#2

Measurement standby

Measurement completed

Measuring

stopped

MANU

TRIG FIN LVL

ERR AGE

--66

Trigger signal ON

Measurement completed

MANU

MANU MEAS

TRIG FIN

LVL

ERR AGE

9#0

Manual measurement

At least 1 second

MANU

MEAS

MANU

TRIG FIN

LVL

ERR AGE

fail

Error occurs

Error detection status

MANU MEAS

Disabled

Main display

When the key is released

Note Power ON reset is a reset process

that runs when the power turns ON.

Press and hold for at least 2 seconds

Or, 3 minutes from the time of startup

Automatic

measurement

in progress

At least

1 second

MANU

TRIG

LVL

ERR

OFF

External

contact

Trigger signal

Start

Manual

monitoring

Starting and Ending Manual Measurement

Manual measurement can be started by pressing the Manual Measurement Key for at least 3 seconds when the channel to measure is selected in the measuring stopped* state in the Operation Level. During manual measurement, MANU indicator is lit.

* The measuring stopped state is

either the measurement standby state, or the state in which a series of measurement operations are complete and the K7GE-MG is waiting for the next trigger signal ON.

4 - 18

Manual measurement cannot start while automatic measurement is in progress.

To be able to start manual measurement, the K7GE-MG must be in the Operation Level, and whether or not the current level is the Operation Level can be known when CH indicator is lit.

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

Press the Manual Measurement Key for at least 1 second during manual measurement to end manual measurement.

Even if the external contact is OFF* during manual measurement, enabled trigger signals are not accepted. Similarly, automatic measurement start by a communications command is also not accepted.

* Relationship between the external contact and trigger signal when the setting

value of the Trigger Signal Reverse setting parameter is OFF.

It takes a few tens of seconds for the measurement value to stabilize after the operation power supply of the K7GE-MG is turned ON. Start manual measurement after 1 minute or more has passed since the operation power supply is turned ON.

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

Error Detection during Manual Measurement

If a measurement error occurs during manual measurement, the application of the Megger voltage stops, fail is displayed to indicate "measurement failed", and this state is maintained (error detection status).

The following three errors may be detected during the execution of manual measurement.

• The voltage monitoring function activates. (Load restart)

• The current limiter activates. (When the insulation resistance is extremely low, etc.)

• The Main Unit cannot recognize the Probe Unit. (Hardware error, etc.)

The K7GE-MG can be recovered from the error detection status by pressing the Manual Measurement Key for at least 1 second. (This is also possible by the power ON reset process by pressing the Reset Key for at least 3 seconds.)

Procedure

4-2 Manual Measurement

The procedure of manual measurement is described as follows:

1. Make sure the load contactor is turned OFF.

2. Make sure the electric charge accumulated in the wiring is

sufficiently discharged.

• Similar to the use of a Megohmmeter, either wait for sufficient

time to elapse based on your experience, or use a voltmeter to ensure that there is no residual voltage due to the electric charge.

3. Make sure the K7GE-MG is in the measuring stopped state in

the Operation Level.

• If automatic measurement is in progress, wait for measurement

to complete. Press the Reset Key for at least 3 seconds to forcibly end automatic measurement and return the K7GE-MG to the measuring stopped (measurement standby) state. However, all measurement values will be cleared in this case.

Measurement standby

TRIG FIN

LVL

MANU ERR AGE

Or, measurement

completed state

TRIG

LVL

MANU

----

FIN

-9#2

ERR AGE

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 19

4 Functions Related to Measurement

----

TRIG FIN

LVL

MANU ERR AGE

MANU

MANU MEAS

TRIG FIN

LVL

ERR AGE

3 seconds

7"6

Measurement value

Stable

MANU

MANU MEAS

TRIG FIN

LVL

ERR AGE

1 second

----

4. Select the channel to perform manual measurement.

• Press the Mode Key several times to set the channel number to

perform manual measurement.

5. Manual measurement is started.

• Press the Manual Measurement Key for at least 3 seconds to

start manual measurement.

6. Wait for the measurement value to stabilize, and then read the

value.

• Due to a capacity component such as the wiring, it may take

some time for the measurement value to stabilize. Read the measurement value after waiting for the value to stabilize.

7. Manual measurement is ended.

• Press the Manual Measurement Key for 1 second to end manual

measurement, and the K7GE-MG will return to measurement standby in the Operation Level. In addition, the measurement will be ended automatically 3 minutes after the start of manual measurement.

8. If necessary, perform manual measurement for the remaining

channels as well.

• Repeat the process to perform manual measurement for the

other channels as well, and check the measurement values.

4 - 20

Insulation Resistance Monitoring Device User’s Manual (N224)

4 Functions Related to Measurement

4-3 Measuring Range and Measuring

Accuracy

The measuring range is between 0.1 and 99.9 MΩ.

The alarm judgment is treated as 0 MΩ for inputs

Display value

Flashes as

99.9

4-3 Measuring Range and Measuring Accuracy

less than 0.1 MΩ and as 99.9 MΩ for inputs greater than 99.9 MΩ.

The display shows 0.0 for inputs less than 0.1 MΩ

10.0

1.0

and flashes 99.9 for inputs greater than 99.9 MΩ.

0.1

0.0

0.1 M 1 M 99.9 M10 M

Measurement

value

The measuring accuracy is as follows:

±5% rdg. ±1 digit (at ambient temperature -10 to 55°C and ambient humidity 25% to 65%)

"rdg." is the abbreviation for "reading" and refers to the read value (displayed numeric value). ±5% rdg. indicates the following range:

(Read value) × (1 - 0.05) to (Read value) × (1 + 0.05)

"digit" is the minimum resolution of the read value. In the K7GE-MG, the minimum resolution of the read value is 0.1 MΩ. Therefore, ±1 digit becomes ±0.1 MΩ.

Thus, for example, if the read value is assumed to be 10.0, the upper and lower limit values will become as follows. Lower limit value: 10.0 × (1 - 0.05) - 0.1 = 9.4 MΩ Upper limit value: 10.0 × (1 + 0.05) + 0.1 = 10.6 MΩ.

That is, the true value will be in the range of 9.4 to

10.6 MΩ.

True value

10.6 M

10.5 M

10.0 M

9.5 M

9.4 M

15.0 M5.0 M 10.0 M

+1 digit

±5% rdg.

-1 digit

(display value)

Read value

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 21

4 Functions Related to Measurement

Voltage monitoring

K7GE-MG

To the microcomputer

Note The above diagram shows only the parts of the

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

Direct current

Sine wave

Thyristor control

Inverter control

4-4 Voltage Monitoring

The voltage in the load lines is monitored to determine whether the load is turned ON or turned OFF. This monitoring is performed at all times, and even when the trigger signal is ON or when the K7GE-MG moves to manual measurement, the measurement operation is not started if the load is turned ON. Also, even if measurement is progressing normally, it immediately stops if the load is turned ON during the measurement.

If the load is determined to be turned ON following trigger signal ON, it results in "measurement failed", and the alarm output turns ON. Refer to Timing Chart for Measurement Failure on page 4-12 in 4-1-4 Timing Charts on page 4-8 for information on the operation when measurement fails.

Next, the judgment conditions for the voltage monitoring function are described.

The voltage value and voltage waveform differ depending on the type of load and the drive method. To detect the waveform, the K7GE-MG monitors the peak value of the waveform.

The threshold value is set as approx. 20 V, and if the absolute value of the peak value is larger than this, it is judged that voltage is present (load turned ON), and if it is smaller than this, it is judged that voltage is absent (load turned OFF).

Therefore, this function is also applicable to loads having a 24 VDC drive.

Moreover, in the case of alternating current waveforms such as sine waves, thyristor control, and inverter control, a frequency of 20 Hz or more is required. For a frequency lower than 20 Hz, it takes too much time from the detection of a waveform until the detection of the next waveform, and it may be judged that voltage is absent (load turned OFF).

The highest voltage that can be monitored is 600 VAC rms (+10%) of sine waves or commercial frequencies.

4 - 22

Insulation Resistance Monitoring Device User’s Manual (N224)

4-5 Current Limiter

Note The above diagram shows only the parts of the internal circuit of the

K7GE-MG that are necessary for explanation.

Rz → 0 MΩ

Current

limiter

Voltage

monitoring

Megger voltage

(50 VDC)

K7GE-MG

Microcomputer

Note The above diagram shows only the parts of the internal circuit of the

K7GE-MG that are necessary for explanation.

This function is used to limit the current flowing through a path to a fixed value (under 3 mA) when applying a Megger voltage.

Due to the flow of overcurrent in the measurement path, the load and the peripheral equipment, as well as the internal circuit of the K7GE-MG may be damaged. Therefore, the overcurrent is limited with the current limiter function. The current limiter of the K7GE-MG is composed of analog components having few delay elements. Therefore, the response speed is extremely fast (μ-second order), and the overcurrent can be instantly suppressed.

4 Functions Related to Measurement

4-5 Current Limiter

L2 L3

K7GE-MG

Next, the cases when the current limiter activates are described.

In the normal state, the measurement

current returns to the measurement circuit of the K7GE-MG via the insulation resistance of the load.

Since the Megger voltage of the

Current

limiter

K7GE-MG is 50 VDC and the lower limit value of the measuring range is 0.1 MΩ, the maximum value of the measurement current is 50 V ÷ 0.1 MΩ = 0.5 mA. Therefore, the current limiter does not activate if measurement can be performed normally.

The current limiter activates in the following three types of cases.

 When the Insulation

Resistance is Extremely Low

When the contactor turns OFF, the load and power line properly turn OFF and the measurement current also passes through the insulation resistance, but the insulation resistance itself is extremely low. For example, when the motor coil is in a metallic case and a short-circuit state.

Voltage

Microcomputer

monitoring

Megger voltage

(50 VDC)

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 23

4 Functions Related to Measurement

Current

limiter

Voltage

monitoring

Megger voltage

(50 VDC)

K7GE-MG

Micro-

computer

Note The above diagram shows only the parts of the internal circuit of the

K7GE-MG that are necessary for explanation.

Inverter

Output zero

Current

limiter

Voltage

monitoring

Megger voltage

(50 VDC)

K7GE-MG

Micro-

computer

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

that are necessary for explanation.

 When the Load Restarts

If the load restarts when applying a Megger voltage, the voltage of the power supply for driving the load is applied between L3 and PE in the figure shown on the right. If a current limiter is not present, a large short-circuit current will flow via the Megger voltage generation circuit of the K7GE-MG. In such a case, the voltage monitoring function activates due to the generation of line voltage. However, because of the intervening software, an instantaneous response of μ-second order cannot be performed. Until that time, the overcurrent is limited by the current limiter.

 When the Drive Voltage

Becomes Zero While the Contactor is ON

In this case, the line voltage is zero. Therefore, the voltage monitoring function judges that the load is turned OFF. If the Megger voltage is applied even though the line voltage is zero, the current flows in a path as shown in the figure on the right without passing through the insulation resistance of the load. If a current limiter is not present, a short-circuit current will flow.

In either case, the current limiter will be operated immediately to avoid hazardous situations. If the current limiter operates, the K7GE-MG immediately stops measuring and is cut off from the load, similar to the voltage monitoring function.

Also, even when the current limiter activates, "measurement failed" occurs, and the alarm output turns ON. Refer to Timing Chart for Measurement Failure on page 4-12 in 4-1-4 Timing Charts on page 4-8 for information on the operation when measurement fails.

4 - 24

Insulation Resistance Monitoring Device User’s Manual (N224)

4-6 Reset Key

Power ON reset

Operation Level

Power ON

----

TRIG FIN

LVL

MANU ERR AGE

FIN

MANU

TRIG

LVL

ERR AGE

-9#2

Measuring

stopped

MANU

TRIG FIN LVL

ERR AGE

--66

Trigger signal ON

MANU

MANU MEAS

TRIG FIN

LVL

ERR AGE

9#0

Manual measurement

RESET

MANU MEAS

Note Power ON reset is a reset process

that runs when the power turns ON.

Measurement standby

Measurement completed

Measurement

completed

At least

3 seconds

At least

3 seconds

RESET

At least

3 seconds

At least

3 seconds

Automatic measurement

in progress

At least 1 second

Or, 3 minutes from the time of startup

Press the Reset Key in the Operation Level for at least 3 seconds to perform the power ON reset process and return to the default.

The defined measurement values, alarm outputs, and alarm output indicator are all cleared.

Even if automatic measurement is in progress, pressing the Reset Key will force the measurement to end. The same applies to manual measurement.

4 Functions Related to Measurement

4-6 Reset Key

This key can also be used to clear the alarm output after checking its status at the work site during the occurrence of an alarm.

Also, if there are many channels, it takes around 10 minutes from the start till the end of automatic measurement, but if automatic measurement is started unintentionally, this key can be used to stop it immediately.

The reset operation can also be executed by a communications command.

The Reset Key is disabled in the Initial Setting Level, Communications Setting Level, and Protect Level. Use it with caution.

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 25

4 Functions Related to Measurement

MEAS

MANU

LVL

ERR AGE

8888

CH1

ALM

MEAS

CH2

ALM

MEAS

CH3

ALM

ALM 2

ALM 1

TRIG FIN

4-7 System Error

A system error is an error which causes the K7GE-MG to be unable to perform the functions that it was primarily meant to perform.

In a normal state in which a system error does not occur, self-diagnosis error output is turned ON, but due to the occurrence of a system error, the self-diagnosis error output is turned OFF, and an external notification is sent.

Name Operation

Main Unit Main display 8888 is lit

ERR indicator Lit

Self-diagnosis error output OFF (normally ON)

ALM 1 and ALM 2 output All OFF

Alarm output indicator Not lit

LVL/CH display Not lit

Other indicators All not lit

Probe Unit MEAS indicator

Not lit

ALM indicator

Discharge of electric charge Stops

Apply Megger voltage Stops

A system error occurs due to the following two causes.

• Duplication of the channel numbers of Probe Units

• Hardware failure

The display and output when a system error occurs are as follows:

4 - 26

If a system error occurs, first of all, make sure that there is no duplication of the channel numbers of Probe Units. If the same channel number is set, correct it and turn ON the power again. If the K7GE-MG can be started normally, you can use it in this condition.

If the channel numbers are not duplicated, a hardware failure has occurred. Contact your OMRON representative for repairs.

Insulation Resistance Monitoring Device User’s Manual (N224)

4-8 Running Time

The K7GE-MG has a built-in electrolytic capacitor. The electrolytic capacitor is impregnated with electrolytic solution that starts to penetrate the sealing rubber from the time of manufacture. As time elapses, the internal electrolytic solution continues to evaporate, resulting in decreased electrostatic capacity and deterioration in other characteristics. Over time, the characteristic deterioration of the electrolytic capacitor prevents the K7GE-MG from being utilized to its full capacity.

4 Functions Related to Measurement

The running time function calculates the approximate time until the K7GE-MG stops functioning at its full capacity due to the deterioration of the

Electrolytic capacitor Characteristics

electrolytic capacitor characteristics, based on the calculated level of deterioration.

AGE indicator will light when the time for the K7GE-MG to stop functioning is reached. You can use this function as a guideline for K7GE-MG replacement.

Guideline

MANU

Running

value

time

TRIG FIN

LVL

----

ERR AGE

The Running Time function can be selected from the Use Running Time setting parameter. The default value is OFF (not used). Refer to 5-10 Use Running Time on page 5-21 for the procedure of the Use Running Time setting parameter.

Regardless of the setting value of the Use Running Time setting parameter, the communications commands can read the current running time as a proportion of the guideline value.

The running time function provides an indication of when the deterioration of the electrolytic capacitor will prevent the K7GE-MG functioning at its full capacity. It does not provide information on failures occurring due to other causes.

4-8 Running Time

Insulation Resistance Monitoring Device User’s Manual (N224)

4 - 27

4 Functions Related to Measurement

Trigger signal

Measurement operation

Response

Time

A TB

TA = TB - t0 TA = TC - t1

Elapsed Time read by the

communications command

4-9 Calculating the Measuring Time

Using the Elapsed Time

The measuring time calculated function calculates the measured time using the clock of the host system.

The K7GE-MG is not equipped with a clock, but you can use this function to know indirectly the measurement time.

As soon as the measurement starts by trigger signal ON, the stopwatch inside the K7GE-MG starts ticking. After the measurement is complete and the measurement value is confirmed, the Elapsed Time is read by the communications command, and the elapsed time of the stopwatch at the time of reception of the communications command is returned. In the host system, the read elapsed time is subtracted from the time of execution of the command by the clock function of the host system, and is set as the time of measurement of the measurement value.

If the K7GE-MG has many measurement channels, it takes approximately 10 minutes from the trigger signal ON to the completion of measurement. This function calculates the time when the trigger signal is ON. Therefore, you can know the approximate measurement time, not the measurement time for each channel.

The time calculated by the stopwatch is reset to start by the following trigger signal ON. Read the Elapsed Time before performing the following operations. If the Elapsed Time is read after performing these operations, undefined numerical values will be read.

• Moving to other than the Operation Level

• Starting manual measurement

• Operating the Reset Key

• Resetting the software with communications command execution

We recommend reading the measurement value and the elapsed time at the same time, otherwise an undefined value may be read.

The elapsed time can be read only by a communications command.

4 - 28

Insulation Resistance Monitoring Device User’s Manual (N224)

Using Setting Parameters

This section describes the K7GE-MG 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)

5 - 1

5 Using Setting Parameters

8888

TRIG FIN

LVL

MANU ERR AGE

Note The Operation Level characters

"1CH" is an example of when the channel number is 1.

Characters Level

Operation

LVL

0 Initial Setting

LVL

Communications Setting

LVL

p Protect

5-1 Levels

The setting items are grouped into "levels". Levels are divided into four types for the K7GE-MG.

Level

Measurement

operation

Description

Operation Possible Normal operation state in which measurement operation is performed when

a trigger signal is received. This is the level immediately after the power is turned ON. The alarm results are reflected in the display, output, and communications status at this level only. At other levels, all alarm results are OFF.

Initial Setting Stops Make initial settings such as alarm values and motor stop waiting time.

At this level, measurement operation is not performed even if a trigger signal is received.

Communications Setting

Stops Make initial settings related to communications, such as the protocol and

baud rate. At this level, measurement operation is not performed even if a trigger signal is received.

Protect Stops Make settings to prevent unintentional key operations. At this level,

measurement operation is not performed even if a trigger signal is received.

The LVL/CH display shows a level when LVL is lit and a channel number when CH is lit.

5 - 2

Insulation Resistance Monitoring Device User’s Manual (N224)

5 Using Setting Parameters

----

TRIG FIN

MANU ERR AGE

 Moving to the Protect

Level

Power ON

At the Operation Level, the

FIN

Power ON

reset

Operation

Level

When the key is released

At least

1 second

TRIG LVL

9#2

ERR AGE

MANU

At least 1 second

Initial Setting

Level

Press and hold for at least 2 seconds

FIN

Less than 1 second

Communications

main display part starts to flash when the Level Key and

Mode Key together ( + ) are pressed for at least 1 second. Press and hold down the keys for at least 2 seconds to move to the Protect Level. To return to the Operation Level, press the Level Key and

At least 1 second At least 1 second

Protect

Level

Press and hold for at least 2 seconds

Note Power ON reset is a reset process that runs when the power turns ON.

TRIG LVL

MANU

At least

1 second

9#2

ERR AGE

Mode Key together ( + ) for at least 1 second.

 Moving to the Initial Setting Level

At the Operation Level, the main display part starts to flash when the Level Key ( ) is pressed for at least 1 second. Press and hold down the keys for 2 more seconds to move to the Initial Setting

Level. To return to the Operation Level, press the Level Key ( ) for at least 1 second.

 Moving to the Communications Setting Level

Press the Level Key ( ) at the Initial Setting Level (for less than 1 second) to move to the

Communications Setting Level. To return to the Initial Setting Level, press the Level Key ( ) (for

less than 1 second). To return to the Operation Level, press the Level Key ( ) for at least 1 second.

Less than

1 second

Setting Level

5-1 Levels

After returning from any level to the Operation Level, the power ON reset process is always executed to clear all measurement values and alarm outputs and return to the measurement standby state.

Insulation Resistance Monitoring Device User’s Manual (N224)

5 - 3

5 Using Setting Parameters

Setting parameter 1

Setting parameter 2

Setting parameter n

alm1 25.0 25.0

Monitoring state

Setting change state

Go to next setting parameter

No operation for 5 seconds

Change setting value with

alm1

LVL

MANU AGEERR

TRIG FIN

2%0

LVL

MANU AGEERR

TRIG FIN

2%0

LVL

MANU AGEERR

TRIG FIN

2#0

LVL

MANU AGEERR

TRIG FIN

alm2

LVL

MANU AGEERR

TRIG FIN

5-2 Setting Parameters and Setting

Values

The setting items for each level are called "setting parameters".

The setting parameters can be moved with the

Mode Key ( ).

The value set for each setting parameter is called the "setting value".

The state where the setting values are displayed is called the "monitoring state", and the state where they can be changed is called the "setting change state".

Use the following operations to display or change the setting values.

1. Press the Mode Key several times to display the setting

parameter to change.

• The setting parameter characters are displayed on the main

display part.

2. Press the Shift Key to enter the monitoring state.

• The setting value is displayed.

• If you only want to check the setting value, press the Mode Key

to move to the next setting parameter.

3. Press the Shift Key again to move to the setting change state.

• The value that can be changed starts flashing.

4. Use the Shift Key and Up Key to change the setting value.

• If no key operation is performed for 5 seconds, the setting value

is saved and the system returns to the monitoring state.

5 - 4

5. Use the Mode Key to save the setting value.

• The changed setting value is saved in the internal memory.

Insulation Resistance Monitoring Device User’s Manual (N224)

OMRON K7GE-MG User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Preface

Terms and Conditions Agreement

Warranty, Limitations of Liability

Application Considerations

Disclaimers

Safety Precautions

Definition of Precautionary Information

Symbols

Precautions for Safe Use

Precaution for Correct Use

Regulations and Standards

Conformance to Safety Standards

Conformance to EN/IEC Standards

Terminology

Manual Structure

Page Structure

Icons

Revision History

Sections in this Manual

CONTENTS

1-1 Overview

1-2 Features

1-3 Model Number Legend

1-5 Nomenclature and Functions

1-6 Internal Block Diagram

1-7 System Configurations

1-8 Safety Precautions

2-1 Procedure

3-1 Dimensions

3-2 Installation

3-3 Setting the Channel Number

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

3-5 I/O Wiring

3-6 Wiring the Communications Cable

3-7 Setting the Unit Number

3-8 Connecting to a Load or Contactor

4-1 Automatic Measurement

4-1-1 Trigger Input

4-1-2 Measurement Steps

4-1-3 Measurement Step Indicator Operation

4-1-4 Timing Charts

4-1-5 Measurement Value Display Automatic Scroll

4-2 Manual Measurement

4-3 Measuring Range and Measuring Accuracy

4-4 Voltage Monitoring

4-5 Current Limiter

4-6 Reset Key

4-7 System Error

4-8 Running Time

5-1 Levels