ProSoft Technology MVI56-MCM User Manual

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MVI56-MCM

ControlLogix Platform

Modbus Communication Module

User Manual

July 24, 2008

Please Read This Notice

Successful application of this module requires a reasonable working knowledge of the Rockwell Automation ControlLogix hardware, the MVI56-MCM Module and the application in which the combination is to be used. For this reason, it is important that those responsible for implementation satisfy themselves that the combination will meet the needs of the application without exposing personnel or equipment to unsafe or inappropriate working conditions.

This manual is provided to assist the user. Every attempt has been made to ensure that the information provided is accurate and a true reflection of the product's installation requirements. In order to ensure a complete understanding of the operation of the product, the user should read all applicable Rockwell Automation documentation on the operation of the Rockwell Automation hardware.

Under no conditions will ProSoft Technology be responsible or liable for indirect or consequential damages resulting from the use or application of the product.

Reproduction of the contents of this manual, in whole or in part, without written permission from ProSoft Technology is prohibited.

Information in this manual is subject to change without notice and does not represent a commitment on the part of ProSoft Technology Improvements and/or changes in this manual or the product may be made at any time. These changes will be made periodically to correct technical inaccuracies or typographical errors.

Warnings

UL Warnings

A Warning - Explosion Hazard - Substitution of components may impair suitability for

Class I, Division 2.

B Warning - Explosion Hazard - When in Hazardous Locations, turn off power before

replacing or rewiring modules. Warning - Explosion Hazard - Do not disconnect equipment unless power has been switched off or the area is known to be nonhazardous.

C Suitable for use in Class I, division 2 Groups A, B, C and D Hazardous Locations or

Non-Hazardous Locations.

ATEX Warnings and Conditions of Safe Usage:

Power, Input, and Output (I/O) wiring must be in accordance with the authority having jurisdiction

A Warning - Explosion Hazard - When in hazardous locations, turn off power before

replacing or wiring modules.

B Warning - Explosion Hazard - Do not disconnect equipment unless power has been

switched off or the area is known to be non-hazardous.

C These products are intended to be mounted in an IP54 enclosure. The devices shall

provide external means to prevent the rated voltage being exceeded by transient disturbances of more than 40%. This device must be used only with ATEX certified backplanes.

D DO NOT OPEN WHEN ENERGIZED.

Electrical Ratings

 Backplane Current Load: 800 mA @ 5 V DC; 3mA @ 24V DC  Operating Temperature: 0 to 60°C (32 to 140°F)  Storage Temperature: -40 to 85°C (-40 to 185°F)  Shock: 30g Operational; 50g non-operational; Vibration: 5 g from 10 to 150 Hz  Relative Humidity 5% to 95% (non-condensing)  All phase conductor sizes must be at least 1.3 mm(squared) and all earth ground

conductors must be at least 4mm(squared).

Markings:

II 3 G 0C <=Ta<= 60C EEx nA IIC T4 DEMKO 07ATEX0710717X

Battery Life Advisory

All modules in the MVI series use a rechargeable Lithium Vanadium Pentoxide battery to backup the 512K SRAM memory, real-time clock, and CMOS. The battery should last for the life of the module.

The module must be powered for approximately twenty hours before it becomes fully charged. After it is fully charged, the battery provides backup power for the CMOS setup and configuration data, the real-time clock, and the 512K SRAM memory for approximately 21 days.

Before you remove a module from its power source, ensure that the battery within the module is fully charged. A fully charged battery will hold the BIOS settings (after being removed from its power source) for a limited number of days. When the battery is fully discharged, the module will revert to the default BIOS settings.

Note: The battery is not user replaceable.

ProSoft® Product Documentation

In an effort to conserve paper, ProSoft Technology no longer includes printed manuals with our product shipments. User Manuals, Datasheets, Sample Ladder Files, and Configuration Files are provided on the enclosed CD and are available at no charge from our web site: http://www.prosoft-technology.com

Printed documentation is available for purchase. Contact ProSoft Technology for pricing and availability.

Asia Pacific: +603.7724.2080 Europe, Middle East, Africa: +33.5.34.36.87.20 Latin America: +1.281.298.9109 North America: +1.661.716.5100

Your Feedback Please

We always want you to feel that you made the right decision to use our products. If you have suggestions, comments, compliments or complaints about the product, documentation or support, please write or call us.

ProSoft Technology 1675 Chester Avenue, Fourth Floor Bakersfield, CA 93301 +1 (661) 716-5100 +1 (661) 716-5101 (Fax) http://www.prosoft-technology.com

MVI56-MCM User Manual July 24, 2008 PSFT.MCM.MVI56.UM.08.07.24

ProSoft Technology ®, ProLinx ®, inRAx ®, ProTalk® and RadioLinx ® are Registered Trademarks of ProSoft Technology, Inc.

Contents MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

Contents

PLEASE READ THIS NOTICE................................................................................................................2

Warnings............................................................................................................................................2

Battery Life Advisory.......................................................................................................................... 3

ProSoft® Product Documentation .....................................................................................................3

Your Feedback Please ...................................................................................................................... 4

1 GUIDE TO THE MVI56-MCM USER MANUAL................................................................................7

2 START HERE....................................................................................................................................9

2.1 System Requirements .......................................................................................................... 9

2.2 Deployment Checklist.........................................................................................................10

2.3 Package Contents .............................................................................................................. 11

2.4 Setting Jumpers..................................................................................................................12

2.5 Install the Module in the Rack ............................................................................................12

2.6 Connect your PC to the Processor..................................................................................... 14

3 USING THE RSLOGIX 5000 V16 ADD ON INSTRUCTION..........................................................15

3.1 Add Module to Rack Configuration.....................................................................................16

3.2 Import Add On Instruction...................................................................................................18

3.3 Download the Sample Program to the Processor .............................................................. 21

4 CONFIGURATION AS A MODBUS MASTER...............................................................................25

4.1 Overview............................................................................................................................. 25

4.2 ModDef Settings .................................................................................................................26

4.3 Master Command Samples................................................................................................ 34

4.4 Floating Point Data Handling.............................................................................................. 40

4.5 Command Control and Event Command ...........................................................................45

5 CONFIGURATION AS A MODBUS SLAVE..................................................................................49

5.1 Overview............................................................................................................................. 49

5.2 ModDef Settings .................................................................................................................50

5.3 Read and Write Same Modbus Address (Pass Thru) ........................................................54

5.4 Slave Configuration ............................................................................................................56

5.5 Further clarification for some parameters in table above. ..................................................57

5.6 Float Point Data Handling...................................................................................................57

6 VERIFY COMMUNICATIONS.........................................................................................................61

6.1 MVI56-MCM Status Data Definition as a Master................................................................61

6.2 Verify Master Communications...........................................................................................62

6.3 Verify Slave Communications.............................................................................................66

7 DIAGNOSTICS AND TROUBLESHOOTING.................................................................................67

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Contents MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

7.1 Reading Status Data from the Module............................................................................... 67

7.2 LED Status Indicators ........................................................................................................ 80

8 REFERENCE.................................................................................................................................. 85

8.1 Product Specifications ....................................................................................................... 85

8.2 Functional Overview........................................................................................................... 87

8.3 Cable Connections........................................................................................................... 105

8.4 MVI56-MCM Database Definition .................................................................................... 111

8.5 MVI56-MCM Configuration Data...................................................................................... 111

8.6 MVI56-MCM Status Data Definition................................................................................. 119

8.7 MVI56-MCM Command Control....................................................................................... 121

8.8 MVI56-MCM User Defined Data Types ........................................................................... 121

8.9 Modbus Protocol Specification......................................................................................... 127

8.10 Using the Sample Program - RSLogix Version 15 and earlier ........................................ 137

9 SUPPORT, SERVICE & WARRANTY......................................................................................... 149

9.1 How to Contact Us: Technical Support............................................................................ 149

9.2 Return Material Authorization (RMA) Policies and Conditions ........................................ 150

9.3 LIMITED WARRANTY ..................................................................................................... 152

INDEX.................................................................................................................................................. 157

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Guide to the MVI56-MCM User Manual MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

1 Guide to the MVI56-MCM User Manual

Function Section to Read Details

Introduction (Must Do)

Verify Communication, Diagnostic and Troubleshooting

Reference Product Specifications Functional Overview Glossary

Support, Service, and Warranty

Index

→

Start Here (page 9)

Verifying Communication (page 61)

Diagnostics and Troubleshooting (page 67)

Reference (page 85) Functional Overview

(page 87, page 137) Product

Specifications (page

85)

Support, Service and Warranty (page

149)

This Section introduces the customer to the module. Included are: package contents, system requirements, hardware installation, and basic configuration.

This section describes how to verify communications with the network. Diagnostic and Troubleshooting procedures.

These sections contain general references associated with this product, Specifications, and the Functional Overview.

This section contains Support, Service and Warranty information.

Index of chapters.

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MVI56-MCM ♦ ControlLogix Platform Guide to the MVI56-MCM User Manual Modbus Communication Module

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Start Here MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

2 Start Here

In This Chapter

 System Requirements .............................................................................9

 Deployment Checklist............................................................................ 10

 Package Contents .................................................................................11

 Setting Jumpers ....................................................................................12

 Install the Module in the Rack ............................................................... 12

 Connect your PC to the Processor ........................................................14

Installing the MVI56-MCM module requires a reasonable working knowledge of the Rockwell Automation hardware, the MVI56-MCM Module and the application in which they will be used.

Caution: It is important that those responsible for implementati on can complete the application without exposing personnel, or equipment, to unsafe or inappropriate working conditions. Safety, quality and experience ar e key factors in a successful installation.

2.1 System Requirements

The MVI56-MCM module requires the following minimum hardware and software components:

 Rockwell Automation ControlLogix™ processor, with compatible power

supply and one free slot in the rack, for the MVI56-MCM module. The module requires 800mA of available power.

 Rockwell Automation RSLogix 5000 programming software version 2.51 or

higher.

 Rockwell Automation RSLinx communication software  Pentium® II 450 MHz minimum. Pentium III 733 MHz (or better)

recommended

 Supported operating systems:

o Microsoft Windows XP Professional with Service Pack 1 or 2 o Microsoft Windows 2000 Professional with Service Pack 1, 2, or 3 o Microsoft Windows Server 2003

 128 Mbytes of RAM minimum, 256 Mbytes of RAM recommended  100 Mbytes of free hard disk space (or more based on application

requirements)

 256-color VGA graphics adapter, 800 x 600 minimum resolution (True Color

1024 × 768 recommended)

 CD-ROM drive  HyperTerminal or other terminal emulator program.

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MVI56-MCM ♦ ControlLogix Platform Start Here Modbus Communication Module

Note: You can install the module in a local or remote rack. For remote rack installation, the modul e requires EtherNet/IP or ControlNet communication with the processor.

2.2 Deployment Checklist

Before you begin configuring the module, consider the following questions. Your answers will help you determine the scope of your project and the configuration requirements for a successful deployment.

1 ____________ Are you creating a new application or integrating the module

into an existing application? Most applications can use the Sample Ladder Logic without any edits to the

Sample Program.

2 ____________ What slot number in the chassis will the MVI56-MCM module

occupy? For communication to occur you must enter the correct slot number in the

sample program.

3 ____________ Are RSLogix 5000 and RSLinx installed?

RSLogix and RSLinx are required to communicate to the CLX processor (1756-L1, L55, L61 & L63). Sample Ladder programs are provided for many versions of RSLogix 5000.

4 ____________ How many words of data do you need to transfer in your

application (from ControlLogix to Module / to ControlLogix from Module)? The MVI module can transfer a maximum of 5000 (16-bit) registers to/from

the CLX processor. The Sample Ladder transfers 600 words to the CLX processor (into the Read Data array) and obtains 600 words from the CLX processor (from the Write Data array)

5 ____________ Will you be using the module as a Modbus Master or Modbus

Slave? Will you be transferring data using Modbus RTU or Modbus ASCII? Modbus is a master/slave network. Only one master is allowed on the Com

line (max 32 devices/RS485). The Master is responsible for polling data from the slaves on the network.

6 ____________ For a Modbus Master, what devices (node ID) and Modbus

addresses do you need to exchange data with on the Modbus network? As a Modbus master, you must know the node ID # of the slave devices you

wish to obtain data from, as well as the Modbus address (coil 0001, register 4001 etc) of the data that must be read from or written to that slave device.

7 ____________ For a Modbus Slave, how many words or bits of data do you

need to send to the master device? The MVI module can send data to a Modbus master as 0x coil data, 1x input

coil data, 3x input registers and 4x holding registers. The sample program transfers 600 (16-bit) words or 9600 bits to the CLX processor, and 600w or 18 bits from the CLX processor.

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Start Here MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

8 Serial Communication Parameters for the Modbus network:

____________ Baud rate? ____________ Data bits? ____________ Parity? ____________ Stop bits? Required for master and slave configurations.

9 ____________ Wiring type to be used (RS232, 422 or 485). Set by jumper

settings (page 12). Required for proper implementation of the module in master and slave

configurations.

Note: If you are installing your module into a new system and plan to use our Sample Ladder Logic, refer to the "handout" included in the module box for simple installation procedures. For version 16 or newer of RSLogix 5000, go to Usi ng the RSLogix 5000 v16 Add On Instruction (page 15). For NEW system installations, go to Sample Ladder Logic in New Application. For EXISTING system installations, go to Integrating the Sample Ladder Logic into an Existing Project (page 142).

Note: Most applications can use the Sample Lad der Logic without any edits to the sample program.

2.3 Package Contents

The following components are included with your MVI56-MCM module, and are all required for installation and configuration.

Important: Before beginning the installation, please verify that all of the following items are present.

Qty. Part Name Part Number Part Description

1 Cable

3 Cable

2 Adapter 1454-9F

MVI56-MCM Module

ProSoft Solutions CD

If any of these components are missing, please contact ProSoft Technology Support for replacement parts.

MVI56-MCM Modbus Communication Module

Cable #15, RS232 Null Modem

Cable #14, RJ45 to DB9 Male Adapter cable

For RS232 Connection to the CFG Port

For DB9 Connection to Module's Port

Two Adapters, DB9 Female to Screw Terminal. For RS422 or RS485 Connections to Port 1 and 2 of the Module

Contains sample programs, utilities and documentation for the MVI56-MCM module.

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MVI56-MCM ♦ ControlLogix Platform Start Here Modbus Communication Module

2.4 Setting Jumpers

If you use an interface other than RS-232 (default), you must change the jumper configuration to match the interface. There are three jumpers located at the bottom of the module.

The following illustration shows the MVI56-MCM jumper configuration:

1 Set the PRT 2 (for application port 1) and PRT 3 (for application port 2)

jumpers for RS232, RS422 or RS485 to match the wiring needed for your application. The default jumper setting for both application ports is RS-232.

2 The Setup Jumper acts as "write protection" for the module's flash memory.

In "write protected" mode, the Setup pins are not connected, and the module's firmware cannot be overwritten. Do not jumper the Setup pins together unless you are directed to do so by ProSoft Technical Support.

2.5 Install the Module in the Rack

If you have not already installed and configured your ControlLogix processor and power supply, please do so before installing the MVI56-MCM module. Refer to your Rockwell Automation product documentation for installation instructions.

Warning: You must follow all safety instructions when installing this or any other electronic devices. Failure to follow safety procedures could result in damage to hardware or data, or even serious injury or death to personnel. Refer to the documentation for each device you plan to connect to verify that suitable safety procedures ar e in place before installing or servicing the device.

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Start Here MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

After you have checked the placement of the jumpers, insert MVI56-MCM into the ControlLogix chassis. Use the same technique recommended by Rockwell Automation to remove and install ControlLogix modules.

Warning: When you insert or remove the module while backplane power is on, an electrical arc can occur. This could cause an explosion in hazardous location installations. Verify that power is removed or the area is non-hazardous before proceeding. Repeated electrical arcing causes excessive wear to contacts on both the module and its mating connector. Worn contacts may create electrical resistance that can affect module operation.

1 Turn power OFF. 2 Align the module with the top and bottom guides, and slide it into the rack

until the module is firmly against the backplane connector.

3 With a firm but steady push, snap the module into place. 4 Check that the holding clips on the top and bottom of the module are securely

in the locking holes of the rack.

5 Make a note of the slot location. You will need to identify the slot in which the

module is installed in order for the sample program to work correctly. Slot numbers are identified on the green circuit board (backplane) of the ControlLogix rack.

6 Turn power ON.

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MVI56-MCM ♦ ControlLogix Platform Start Here Modbus Communication Module

Note: If you insert the module improperly, the system may stop working, or may behave unpredictably. Note: If you are installing MVI56-MCM with other modul es connected to the PCI bus, the peripheral modules will not have holding clips. Make sure all of the modules are ali gned with their respective slots before you snap them into place.

2.6 Connect your PC to the Processor

1 Connect the right-angle connector end of the cable to your controller at the

communications port.

2 Connect the straight connector end of the cable to the serial port on your

computer.

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Using the RSLogix 5000 v16 Add On Instruction MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

3 Using the RSLogix 5000 v16 Add On

Instruction

In This Chapter

 Add Module to Rack Configuration ........................................................16

 Import Add On Instruction...................................................................... 18

 Download the Sample Program to the Processor..................................21

Important: If you are using an older version of RSLogix 5000 (version 15 or older), please refer to Sample Ladder Logic in New Application or Integrating the Sample Ladder Logic into an Existing Project (page 142).

If you have RSLogix 5000 version 16 or newer, you can use an Add On Instruction to simplify the task of configuring the module, either as a new application, or within an existing application.

The ProSoft Solutions CD-ROM included in the package with the module contains ladder logic, product manuals and utility programs for all ProSoft Technology products.

Copy the manuals and sample program from the CD-ROM

1 Insert the ProSoft Solutions CD-ROM into the CD drive of your PC. Wait for

the startup screen to appear.

2 On the startup screen, click Product Documentation. This action opens an

Explorer window. Files are arranged by type:

o The Ladder Logic folder contains sample programs for each module,

arranged by processor type, and then by product name. The sample programs for your module are in the ControlLogix/MVI56/MVI56-MCM folder.

o The Manuals folder contains product manuals and datasheets in Adobe

Acrobat Reader format (PDF) for each module, arranged in the same way as the Ladder Logic folder.

o The Utilities folder contains additional programs and tools required for

some ProSoft modules. Refer to your user manual to determine if you need to use or install any of these additional tools.

3 In the Explorer window, navigate to the files you need, and then copy them to

a location on your hard drive.

Download the manuals and sample program from the ProSoft Technology web site

You can always download the latest version of the sample ladder logic and user manuals for the MVI56-MCM module from the ProSoft Technology web site, at http://www.prosoft-technology.com/support/downloads

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MVI56-MCM ♦ ControlLogix Platform Using the RSLogix 5000 v16 Add On Instruction Modbus Communication Module

From that link, navigate to the download page for your module and choose the sample ladder program to download for your version of RSLogix 5000 and your processor.

3.1 Add Module to Rack Configuration

As with any project, the first step is to define the module in the I/O configuration of your project. This is done within the Controller Tree, as shown here:

1 Select the "1756 Backplane" object and select this object. Right mouse click

on this object, and select the "New Module…" option, as shown below.

This action opens the Select Module dialog box.

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Using the RSLogix 5000 v16 Add On Instruction MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

2 Select "1756-MODULE" option and then click the

opens the New Module dialog box.

3 Set the parameters to match the illustration above. Make sure that "Comm

Format Data -INT" is selected. Set the Slot parameter to the slot number used in your project.

4 Click

to open the Module Properties dialog box.

button. This action

An RPI time of the default 5.0 ms will work well for the MVI56-MCM module in a local I/O rack. If the module is being used in a remote rack over Control Net (for Redundancy systems for example) then this RPI time must be raised to values between 20 and 100 ms in most applications. Also ProSoft has a module that is specifically designed for this application, the MVI56-MCMR module. Contact Technical Support for more information about this module and other options.

5 When you have finished setting the RPI times, click the

save the module configuration and dismiss the dialog box.

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button to

MVI56-MCM ♦ ControlLogix Platform Using the RSLogix 5000 v16 Add On Instruction Modbus Communication Module

The module is now defined in the I/O configuration. You should now be able to see the module in the I/O tab of the Controller Tree, as shown in the following illustration:

3.2 Import Add On Instruction

1 Open your application in RSLogix 5000. 2 Expand the Tasks folder, and then expand the Main Task folder. 3 On the Main Program folder, click the right mouse button to open a shortcut

menu. On the shortcut menu, choose New Routine.

4 In the New Routine dialog box, enter the name and description of your

routine, and then click OK.

5 Select an empty rung in the new routine, and then click the right mouse

button to open a shortcut menu. On the shortcut menu, choose "Import Rung…".

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Using the RSLogix 5000 v16 Add On Instruction MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

6 Select the MVI56MCM_AddOnRung.L5X file

7 The following window will be displayed showing the controller tags to be

created during the import procedure:

8 Click OK to confirm the import. RSLogix will indicate that the import is under

progress:

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MVI56-MCM ♦ ControlLogix Platform Using the RSLogix 5000 v16 Add On Instruction Modbus Communication Module

When the import is completed, the new rung with the Add-On instruction will be visible as shown in the following illustration.

The procedure has also imported new user defined data types, data objects and the Add-On instruction to be used in your project.

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Using the RSLogix 5000 v16 Add On Instruction MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

3.3 Download the Sample Program to the Processor

Note: The key switch on the front of the ControlLogix module must be in the REM position.

To download the sample program from RSLogix 5000 to the ControlLogix processor

1 If you are not already online to the processor, open the Communications

menu, and then choose Download. RSLogix will establish communication with the processor.

2 When communication is established, RSLogix will open a confirmation dialog

box. Click the Download button to transfer the sample program to the processor.

3 RSLogix will compile the program and transfer it to the processor. This

process may take a few minutes.

4 When the download is complete, RSLogix will open another confirmation

dialog box. Click OK to switch the processor from Program mode to Run mode.

Note: If you receive an error message during these steps, refer to your RSLogix documentation to interpret and correct the error.

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MVI56-MCM ♦ ControlLogix Platform Using the RSLogix 5000 v16 Add On Instruction Modbus Communication Module

3.3.1 Configuring RSLinx

If RSLogix is unable to establish communication with the processor, follow these steps:

1 Open RSLinx. 2 Open the Communications menu, and choose Configure Drivers.

This action opens the Configure Drivers dialog box.

Note: If the list of configured drivers is blank, you must first choose and configure a driver from the Available Driver Types list. The recommended driv er type to choose for serial communicatio n with the processor is "RS-232 DF1 Devices".

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Using the RSLogix 5000 v16 Add On Instruction MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

3 Click to select the driver, and then click Configure. This action opens the

Configure Allen-Bradley DF1 Communications Device dialog box.

4 Click the Auto-Configure button. RSLinx will attempt to configure your serial

port to work with the selected driver.

5 When you see the message "Auto Configuration Successful", click the OK

button to dismiss the dialog box.

Note: If the auto-configuration procedure fails, verify that the cables are connected correc tly between the processor and the serial port on your computer, and then try again. If you ar e still unable to auto-configure the port, refer to yo ur RSLinx documentation for further troubleshooti ng steps.

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Configuration as a Modbus Master MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

4 Configuration as a Modbus Master

In This Chapter

 Overview ...............................................................................................25

 ModDef Settings.................................................................................... 26

 Master Command Samples ................................................................... 34

 Floating Point Data Handling................................................................. 40

 Command Control and Event Command...............................................45

4.1 Overview

This section describes the configuration of the module as a Modbus Master device. With Modbus communication, the master is the only device on the line that will initiate communications. A master device will issue a request message, and then wait for the slave to respond. When the slave responds, or a timeout has occurred, the module (as a master) will then move on to the next command in the list.

Configuration of the module as a master must be done in the following three locations:

1 ModDef: configures which of the 5000 data registers of the module will be

sent to the ControlLogix Processor (data placed in the ReadData tags) and which of those same 5000 registers will be obtained from the ControlLogix Processor (data obtained from the WriteData tags).

2 PortX: configures the port. Parameters such as baud rate, data bits, and stop

bits are setup here.

3 PortXMasterCommand: you are building a polling table for the module as a

master. Here you tell the module what devices are connected on the Modbus network, what data to read/write with those devices, and where that data is obtained/stored within the modules 5000 register memory.

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MVI56-MCM ♦ ControlLogix Platform Configuration as a Modbus Master Modbus Communication Module

4.2 ModDef Settings

The first step in the configuration of the module is in the tag labeled MCM.CONFIG.ModDef. This will setup which of the 5000 data registers will be written to the MVI module, and which of the 5000 data registers will be read from the MVI module. The read and write data locations will be used later in the Master Command section when we configure the IntAddress within each MasterCommand. Below are the values from our sample ladder program.

The WriteStartReg will be used to determine the starting register location for WriteData [0 to 599] and the WriteRegCnt will be used to determine how many of the 5000 registers will be used for information to be written out to the module. The sample ladder file will setup 600 registers for write data, labeled

MCM.WriteData[0 to 599].

Label Description

WriteStartReg

WriteRegCnt

ReadStartReg

ReadRegCnt

BPFail

ErrStatPtr

Determines where in the 5000 register module memory to place the data obtained from the ControlLogix processor from the WriteData tags.

Sets how many registers of data the MVI module will request from the CLX processor. Because the module pages data in blocks of 200 words, this number should be evenly divisible by 200.

Determines where in the 5000 register module memory to begin obtaining data to present to the CLX processor in the ReadData tags.

Sets how many registers of data the MVI module will send to the CLX processor. This value should also be a multiple of 200.

Sets the consecutive number of backplane failures that will cause the module to stop communications on the Modbus network. Typically used when the module is configured as a slave.

Also used mainly when the module is setup as a slave. This parameter places the STATUS data into the database of the module.

The sample configuration values set up the module database for WriteData[0 to

599] to be stored in the module memory at register 0 to 599, and ReadData[0 to 599] to be stored in the module memory at registers 1000 to 1599 like shown

below.

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Configuration as a Modbus Master MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

The following is the sample configuration layout of the tags and addressing.

The MVI56-MCM sample program is configured for 600 registers of ReadData and 600 registers of WriteData. In most applications, this is plenty of data tags for an application, but in some cases you may require more user data. To increase the array size for your application, follow the steps described below.

Because the module pages data in blocks of 200 registers at a time, you will want to keep this as a number divisible by 200.

Note: Changing the array size may zero out all tags in the MCM tag location, usually at Step 3 of this procedure. Make sure you have saved any configuration you have alrea dy done so you can reference this later in case the data values in the MCM array are reset to 0.

For example, if your application will require 1000 words of read data, instead of the default 600 words, follow the steps below to make this change.

1 Click on MCMDATA from the User-Defined data type in the Controller

Organization List.

2 Change ReadData array from INT[600] to INT[1000] as shown.

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3 Click on the Apply button located at bottom of window.

Note: You may get a message telling you that data values have been reset, make sure that you have saved a backup copy of your program if you have parameters configu r ed.

4 Next, click Controller Tags. This action opens the MVI56MCM window.

Verify that the Monitor Tags tab is selected (see Monitor/Edit tags on bottom of window).

Note: Be aware that the window parameters can be changed by clicking between Monitor and Edit tags. You can use the scroll bar to view para meter columns for each tag too.

5 Click on [+] to open the MCM.CONFIG.ModDef section and change the

ReadRegCnt parameter from the default 600 to 1000 for your application.

6 Click ReadData to open ladder file and go to rung #2 of this file. 7 Change the High Limit on the LIM statement to allow for 5 blocks of data.

(1000 registers / 200 registers per block = 5 blocks of data) This step is shown below.

8 Verify the change to this rung. Toggle the 9 Save and download ladder to the processor. 10 When Online with the ControlLogix processor, toggle the

MCM.CONTROL.WarmBoot bit to download the change made in Step 5 to the processor.

Note: Any changes made to the MCM.CONFIG array must be downloaded to the MVI56MCM module. The use of the MCM.CONTROL.WarmBoot or MCM.CONTROL.ColdB oot bit will force the MVI56MCM module to re- read the configuration from the ControlLogix processor.

object within RSLogix 5000.

This holds true for changes made to the WriteData array.

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For modifying the WriteData array, change the High Limit value of the LIM statement in rung #3 of the WriteData ladder. Also make sure that the ReadData and WriteData arrays do not overlap in the module memory. If you have an application that requires 2000 words of WriteData, starting at register 0, then your MCM.CONFIG.ModDef.ReadStartReg should be set to a value of 2000 or greater.

4.2.1 Port Setup

The following section describes the parameters necessary within the MCM.CONFIG.PortX section of the controller tags that are used when the module is setup as a Modbus Master device. Port 1 and Port 2 each have their own set of parameters to configure.

Note: Any changes made within either the MCM.CONFIG array must be downloaded to the MVI56MCM module by setting either the WarmBoot, ColdBoot, or cycling power to the module.

Any parameters not mentioned in this section are not used when the module is configured as a Modbus Master. Parameters in BOLD are required for all applications as a master.

Verify you are in Monitor Tags mode. Then use scroll bar at bottom to view description of each parameter. The following table uses that information.

Label Description Enabled Type

FloatFlag

FloatStart

Protocol Baudrate Sets the baud rate that the port will operate at. Valid values for this field

Parity DataBits StopBits

RTSOn 0 to 65535 milliseconds delay before data RTSOff 0 to 65535 milliseconds delay after data UseCTS 0 = No, 1 = Yes to use CTS modem line CmdCount

1 = enable port, 0 = disable port Master = 0 0 = No Floating point data, 1 = Use Floating point data. See "Floating

Point Support (page 40)" for more information. Register offset in message for floating data point. See "Floating Point

Support (page 40)" for more information. 0 = Modbus RTU mode, 1 = Modbus ASCII mode

are 110, 150, 300, 600, 1200, 4800, 9600, 19200, 384 or 3840 (for 38,400 baud), 576 or 5760 (for 57,600 baud) and 115,1152, or 11520 (for 115,200 baud)

0 = None, 1 = Odd, 2 = Even Modbus RTU mode = 8 Modbus ASCII mode = 8 or 7 Valid values are 1 or 2.

Command list count

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Label Description

MinCmdDelay 0 to 65535 milliseconds min. time between each commands

Ex: A value of 10 will cause the module to wait 10 milliseconds between the issuance of each Modbus master command.

CmdErrPtr RespTO RetryCount

ErrorDelayCntr 0 to 65535 Command cycle count if error InterCharacterDelay

Further clarification for some parameters in table above.

Parameter Description CmdCount Command count list 100 = causes the module to look at

CmdErrPtr Set Master Command Errors location. Each command will reserve one for

RespTO 1000 = 1000 milliseconds (1 second) before it will either reissue the

ErrorDelayCntr

InterCharacterDelay

Internal DB location to place command error list 0 to 65535 milliseconds response timeout for command Retry count for failed request

0 to 65535 milliseconds time between characters to signal end of message

MCM.CONFIG.PortX. MasterCommand[0]-[99]. 10 = cause commands [0]-[9] to be processed. Sets how many registers will be used for error codes as set in the CmdErrPtr value.

the command error code. See "Verifying Communications" of this manual. CmdErrPtr value should be within the range of the ReadData array, per MCM.CONFIG.ModDef of this manual.

command (as set in the RetryCount) or if the RetryCount has already been met, then it will move on to the next command in the list.

Sets consecutive commands to that slave will be skipped if a command has gone into error. For example, if a command to slave 1 has gone into error (RespTO has elapsed, and RetryCount has been met), the module will skip the next X number of commands in the list to node number 1. This can be useful in applications where a slave device is taken offline, as the module will try the first command to that slave, and then skip the next X number of commands to that slave so that time is not lost on trying to poll information from a slave device that is not on the network.

Sets the Inter Character Delay for the module. Within Modbus RTU a character gap or quiet time on the line signals the end of the message. This is typically 3.5 character widths, as specified by the Modbus protocol. In some Radio or Modem applications, there may be more of a delay between characters.

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4.2.2 Master Command Configuration

The following section describes the communications with the master port and the slave devices that are connected to that port.

Verify you are in Monitor Tags mode. Then use the scroll bar at bottom to view description of each parameter. The following table uses that information.

Label Description

Enable 0 = Disabled

Command will not be executed, but can be enabled using command control option in ladder logic.

1 = Enabled Command is enabled and will be sent out to the target device. 2 = Conditional Write Only for Func 5, 15, 6, or 16 data will be written out to the target device

only when the data to be written has changed.

IntAddress

PollInt

Count

Determines where in the module's 5000 register database the data will be stored to or written from. On a Read command this will determine once the information has been read from a slave, where it will be placed in the module database. On read commands you will want to configure this for a location that is setup for ReadData. The internal database location of the ReadData and WriteData tags is determined by the configuration setup in the MCM.ModDef tag location.

For write data the IntAddress will determine where to obtain the information to be written out to the slave device. This will need to be a location that is setup as WriteData.

Note: When using a bit level command you will want to define this field at the bit level. For instance, when using a function code 1, 2 for a Read command you will need to have a value of 16000 to place the data in MCM.ReadData[0] (register 1000 * 16 bits per register = 16000).

Values in this field will represent the number of seconds that a master device will wait before issuing this command.

Sets how many continuous words (FC 3, 4, and 16) or bits (FC 1, 2 and

15) will be requested from the slave device. Valid values are 1 to 125 words for function codes 3, 4 and 16, while

you can specify a range of 1 to 2000 for function codes 1, 2 and 15. Note: These values are maximum allowed within Modbus protocol,

some devices may support less than maximum allowed.

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Label Description

Swap

Node

Func

Typically used when reading floating point data, swaps the data read from the slave device before it is placed into the module memory. For instance, you receive 4 bytes of data from the slave (ABCD).

0 = No swapping (ABCD) 1 = Word pairs switched (CDAB) 2 = Bytes and words switched (DCBA) 3 = Bytes swapped (BADC) Node address of the device on the network to read data from, or write

data to. Valid addresses are 1 to 247 with address 0 being reserved for broadcast write commands (will broadcast a Write command to all devices on the network).

Determines the modbus function code that will be issued in the command to the slave device. Valid values for this field are as follows:

1 = Read Coil Status

This will read modbus addresses 0001 to 9999. These are bit values used to indicate coil status, and can also be written to using Function Code 5 or 15.

2 = Read Input Coils

This will read modbus addresses 10001 to 29999. Like Function Code 1, these are also bit values, but Function Code 2 values are Read Only data values, while FC 5 and 15 will write to the Coil Status values.

3 = Read Holding Registers

This is to be used for Modbus addresses 40001 to 47999. This is a 16 bit word value, and can be written to using Function Codes of 6 and 16.

4 = Read Input Registers

Will read modbus addresses 30001 to 39999. These are also 16 bit word values, but are Read Only data, and cannot be written to by the master.

5 = Write Single Coil Status

This will write to modbus addresses 0001 to 9999. This command will write to only one coil. If you want to write to multiple coils you will need to use Function Code 15.

6 = Write Single Register

For modbus addresses 40001 to 47999. This will write one single register value out to a slave device. For multiple register writes you will need to use Function Code 16.

15 = Multiple Coil Write

This function code will write multiple coil values to the slave addresses 0001 to 9999.

16 = Multiple Register Write

Will write multiple register values to the slave device at addresses 40001 to 49999.

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Label Description

DevAddress

Used to indicate the modbus slave address for the register or registers associated with that command. This is the offset address for the modbus slave device. With modbus, to read an address of 40001, what will actually be transmitted out port is Function Code 03 (one byte) with an address of 00 00 (two bytes). This means that to read an address of 40501, you would want to put a Func of 3 with a DevAddress of 500.

This applies to modbus addresses 10001 to 47999. Below is a definition that will help with your DevAddress setup: FC 1, 5, or 15 DevAddress = Modbus address in device - 0001 Example: Modbus address 0001 = DevAddress 0 Modbus address 1378 = DevAddress 1377 FC 2 DevAddress = Modbus address in device - 10001 Example: Modbus address 10001 = DevAddress 0 Modbus address 10345 = DevAddress 344 FC 3, 6, or 16 DevAddress = Modbus address in device - 40001 Example: Modbus address 40001 = DevAddress 0 Modbus address 40591 = DevAddress 590 FC 4 DevAddress = Modbus address in device - 30001 Example: Modbus address 30001 = DevAddress 0 Modbus address 34290 = DevAddress 4289

4.2.3 More Master Command Configuration

Q. My Modbus addressing for my device does not look like what was described above?

While the above information will handle most devices that you are looking to setup, some device manufacturers have chosen to show their Modbus addressing differently. The two most common schemes are six-digit addressing (400101, 301000, etc…) and some devices show their addressing already as an offset address (the address that actually goes out on the Modbus communication line). This is an example.

Actual Values (Input Registers) Addresses: 0200 to 0E1F

STATUS 0200 Switch Input Status 0201 LED Status Flags 0202 LED Attribute Flags 0203 Output Relay Status Flags

If your device manufacturer gives you addressing like this, "Input Registers" then you will use Function Code 4, and then place the address shown in the DevAddress field. Also, most manufacturers that show this type of addressing will list the address in hex, as is the case with the device shown above. So for this example device, you will want to use Func = 4 (Input Registers) with a DevAddress of 512 decimal (200h) to read the "Switch Input Status" value.

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Q. My slave shows addressing like 400,001 or 301,345?

For the 6 digit addressing, you will want to use the same function codes and configuration as setup above, just the starting address has changed. Below is a definition that will help with your DevAddress setup: FC 1, 5, or 15 DevAddress = Modbus address in device - 0001 Example: Modbus address 0001 = DevAddress 0 Modbus address 1378 = DevAddress 1377 FC 2 DevAddress = Modbus address in device - 100001 Example: Modbus address 100001 = DevAddress 0 Modbus address 100345 = DevAddress 344 FC 3, 6, or 16 DevAddress = Modbus address in device - 400001 Example: Modbus address 400001 = DevAddress 0 Modbus address 400591 = DevAddress 590 FC 4 DevAddress = Modbus address in device - 300001 Example: Modbus address 300001 = DevAddress 0 Modbus address 304290 = DevAddress 4289 For example, our device listed above could show their addressing as follows.

To read the same parameter "Switch_Input_Status", you would still issue a FC 4, and use a DevAddress of 512 decimal.

4.3 Master Command Samples

The following examples are going to guide you through the configuration of some of the Modbus Master commands.

4.3.1 Read Holding Registers 4xxxx (Modbus Function Code 3)

The 4x holding registers are used for Analog Values such as Pressure, Temperature, Current, and so on. These are 16 bit register values, but can also be used for the storage of Floating Point data (see Floating Point Support in this manual). These same Modbus addresses can be written to using a Modbus Function Code 6 or 16.

Below is a sample command to read Modbus addresses 40001 to 40010 of node 1 on the Modbus network.

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Label Description

Enable = 1

Causes the module to send the command every time it goes through the command list.

IntAddress = 1000

Places the data read from the slave device into the module at address

1000. IntAddress 1000 of the module memory will be copied into the tag

MCM.DATA.ReadData[0]. Count = 10 Reads 10 consecutive registers from the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 3 Issues a Modbus Function code of 3 to Read Holding Registers. DevAddress = 0 Function Code 3, DevAddress of 0 will read address 40001

Along with a count of 10, this command reads 40001 to 40010.

4.3.2 Read Input Registers 3xxxx (Modbus Function Code 4)

Like the 4x holding registers, 3x input registers are used for reading analog values that are 16 bit register values, but can also be used for the storage of floating point data (see Floating Point Support in this manual). Unlike the 4x registers, 3x registers are Read only, and cannot be written to.

Below is a sample command to read Modbus addresses 30021 to 30030 of node 1 on the Modbus network.

Label Description

Enable = 1

Causes the module to send the command every time it goes through

the command list. IntAddress = 1010

Places the data read from the slave device into the module at address

1010. IntAddress 1010 of the module memory will be copied into the tag

MCM.DATA.ReadData[10]. Count = 10 Reads 10 consecutive registers from the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 4 Issues a Modbus Function code of 4 to Read Input Registers. DevAddress =20 Function Code 4 DevAddress of 20 will read address 30021

Along with a count of 10, this command reads 30021 to 30030.

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4.3.3 Read Coils 0xxxx (Modbus Function Code 1)

Modbus Function Code 1 reads the Coils addressed at 0001 to 9999 from a slave device. These are bit values that are read using Modbus Function Code 1, and can be written to using Function Code 5 or 15. Within a slave device, this is an individual bit value. Thus the IntAddress field must be defined down to the bit level within your MasterCmd.

Below is a sample command to read Modbus addresses 0321 to 0480 of node 1 on the Modbus network.

Label Description

Enable = 1

IntAddress = 16320

Count = 160 Reads 160 consecutive bits from the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 1 Issues a Modbus Function code of 1 to Read Coils. DevAddress = 320 Function Code 1, DevAddress of 320 will read address 0321

Causes the module to send the command every time it goes through the command list.

Places the data read from the slave device into the module at address

16320. IntAddress 16320 of the module memory will be copied into the tag MCM.DATA.ReadData[20] because 16320 represents a bit address within the memory of the MVI56-MCM module (16320 / 16 = register

1020).

Along with a count of 160, this command reads 0321 to 0480.

4.3.4 Read Input Coils 1xxxx (Modbus Function Code 2)

Used to read Input Coils from a slave device, these are single bit addresses within a Modbus slave device. Unlike Coils 0xxx, the Input Coils are Read Only values and cannot be written to by a Modbus Master device. Also like the Coils 0xxx, the IntAddress field of this command is defined down to the bit level within the module memory.

Below is a sample command to read Modbus addresses 10081 to 10090 of node 1 on the Modbus network.

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Label Description

Enable = 1

IntAddress = 16480

Count = 16 Reads 16 consecutive registers from the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 2 Issues a Modbus Function code of 2 to Read Input Coils. DevAddress = 80 Function Code 2, DevAddress of 80 will read address 10081

Causes the module to send the command every time it goes through

the command list.

Places the data read from the slave device into the module at address

16480. IntAddress 16480 of the module memory will be copied into the

tag MCM.DATA.ReadData[30] (bit16480 / 16 = register 1030).

Along with a count of 16, this command reads 10081 to 10096.

4.3.5 Write Single Coil 0xxxx (Modbus Function Code 5)

Used to write a Coil of a slave device, these are single bit addresses within a Modbus slave device. The IntAddress field of this command is defined down to the bit level within the module memory, and should come from an area of memory that has been defined within the MCM.DATA.WriteData area (this is configured within MCM.CONFIG.ModDef.

Below is a sample command to write Modbus addresses 0513 of node 1 on the Modbus network, only when the data associated with the IntAddress has changed.

Label Description

Enable = 2

IntAddress = 160

Count = 1 Will write a single bit to the device (FC5 will 1 support a count of 1). Node = 1 Issues the Modbus command to node 1 on the network. Func = 5 Issues a Modbus Function code of 5 to write a single coils. DevAddress = 512 Function Code 5, DevAddress of 512 will read address 0513

Causes the module to send the command only when the data within the

IntAddress field of the module has changed.

Will write the data to the slave device when the value at WriteData[10].0

has changed. Because this is a bit level command, the IntAddress field

must be defined down to the bit level.

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4.3.6 Write Multiple Coils 0xxx (Modbus Function Code 15)

Used to write multiple Coils in the 0xxx address range, this function code will allow you to set multiple Coils within a slave device using the same Modbus command. Not all devices will support this function code, so verify this with your slave device documentation before implementing this function code.

This function code will also support the Enable code of 2, to write the data to the slave device only when the data associated within the IntAddress field of the module has changed. The IntAddress is once again defined down to the bit level as a Function Code 15 is a bit level Modbus function.

Below is a sample command to write Modbus addresses 0001 to 0016 of node 1 on the Modbus network.

Label Description

Enable = 2

IntAddress = 320

Count = 16 Writes 16 consecutive bits to the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 15 Issues a Modbus Function code of 15 to write multiple coils. DevAddress = 0 Function Code 15, DevAddress of 0 will read address 0001

Causes the module to send the command to the slave device only when the data associated within the IntAddress of the MVI56-MCM module memory has changed.

Writes the data in bit 320 of the module memory to the slave device. Based on the MCM.CONFIG.ModDef setting, this would be the data in MCM.DATA.WriteData[20].0 to [20].15 in the ladder logic.

Along with a count of 16, this command writes to 0001 to 0016.

4.3.7 Write Holding Register 4xxxx (Modbus Function Code 6)

Used to write to Modbus Holding Registers 4xxxx, this function code will write a single register to the slave device. The Enable code can be set to a value of 1 for a continuous write, or a value of 2 to write the data to the slave device only when the data associated with the IntAddress field has changed.

Below is a sample command to write Modbus addresses 41041 of node 1 on the Modbus network.

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Label Description

Enable = 1

Causes the module to send the command every time it goes through

the command list. IntAddress = 5

Writes the data from address 5 of the module memory to the slave

device. Based on the MCM.CONFIG.ModDef configuration, this will

take the data from MCM.DATA.WriteData[5] and write that information

out to the slave device. Count = 1 Writes 1 register (16 bit) to the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 2 Issues a Modbus Function code of 6 to write a single register. DevAddress = 1040

Function Code 6, DevAddress of 1040 will write to address 41041 of the

Modbus slave device.

4.3.8 Write Multiple Registers 4xxxx (Modbus Function Code 16)

Used to write to Modbus Holding Registers 4xxxx, this function code will write multiple registers to the slave device. The Enable code can be set to a value of 1 for a continuous write, or a value of 2 to write the data to the slave device only when the data associated with the IntAddress field has changed.

Below is a sample command to write Modbus addresses 41051 to 41060 of node 1 on the Modbus network.

Label Description

Enable = 2

IntAddress =30

Count = 10 Writes 10 consecutive registers to the slave device. Node = 1 Issues the Modbus command to node 1 on the network. Func = 16 Issues a Modbus Function code of 16 to write Holding Registers. DevAddress = 1050 Function Code 16, DevAddress of 1050 will write address 41051.

Causes the module to send the command only when the data

associated with the IntAddress of the module has changed.

Writes the data from Internal Address 30 of the module memory to the

slave device. Based on the MCM.CONFIG.ModDef configuration, this

will write the data from MCM.DATA.WriteData[30]-[39] to the slave

device.

Along with a count of 10, this command writes 41051 to 41060 of the

slave device.

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4.4 Floating Point Data Handling

In many applications, it is necessary to read or write floating point data to the slave device. The ProSoft sample ladder only provides an INT array for the ReadData and Write Data array (16 bit signed integer value). In order to read/write floating point data to and from the slave device, it is necessary to add additional ladder to handle the conversion of the data to a REAL data type within the ControlLogix processor. This is very easy to accomplish. Below are some examples of reading/writing floating point data to a slave device, and when to use the Float Flag and Float Start parameters within the module configuration. For all applications, floating point data can be read from a device without any changes to the Float Flag and Float Start parameters. These parameters are only required to be configured when issuing a Write command to a device that utilizes a single Modbus address like 47001, to represent a single floating point value.

4.4.1 Read Floating Point Data

Here is the addressing of a slave device, with a parameter "Energy Consumption" that is shown as two registers 40257 and 40258.

Value Description Type

40257 -------- KWH Energy Consumption Float, upper 16 bits 40258 KWH Energy Consumption Float, upper 16 bits

To issue a Read command to this parameter, the following configuration should be used.

Parameter Value Description

Enable 1 Sends the command every time through the command list. IntAddress 1000

PollInt 0 No delay for this command. Count 2

Swap 0

Node 1 Sends the command to Node #1. Func 3 Issues a Modbus FC 3 to "Read Holding registers." DevAddress 256

Places data at address 1000 of the module memory. Based on the configuration in ModDef this will put the data at the tag MCM.DATA.ReadData[0].

Reads 2 consecutive registers from the slave device. These 2 Modbus registers will make up the "Energy Consumption" floating point value.

Swap Code Description

1 Words - The words are swapped (1234=3412) 2

Along with the FC 3, DevAddress 256 will read Modbus address 40257 of the slave device.

None - No Change is made in the byte ordering (1234 = 1234)

Words & Bytes - The words are swapped then the bytes in each word are swapped (1234=4321)

Bytes - The bytes in each word are swapped (1234=2143)

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Along with the FC 3, DevAddress 256 will read Modbus address 40257 of the slave device.The above command will read 40257 and 40258 of the Modbus Slave #1 and place that data in MCM.DATA.ReadData[0] and [1].

Within the controller tags section of the ControlLogix processor, it is necessary to configure a tag with the data type of "REAL" as shown in the following illustration.

[+] Energy_Consumption REAL[1] Float

Copy data from the MCM.DATA.ReadData[0] and [1] into the tag "Energy_Consumption" that has a data type of REAL. Use a COP statement within the ladder logic. Here is an example.

Because the tag MCM.DATA.ReadData[0] should only be used within the above configured command, an unconditional COP statement can be used.

Notice the length of the COP statement is a value of 1. Within a Rockwell Automation processor, a COP statement will copy the required amount of "Source" values to fill the "Dest" tag for the Length specified.

Therefore the above statement will copy ReadData[0] and [1] to fill the 32 bits required for the tag "Energy_Consumption".

Note: Do not use a MOV statement. A MOV will convert the data from the Source register to the destination register data type. This is a cast statement and will convert the data.

4.4.2 Read Multiple Floating Point Registers

Below is an example to read Multiple Floating Point values and device addresses.

Value Description Type

40261 KW Demand (power) Float. upper 16 bits 40263 VAR Reactive Power Float. upper 16 bits 40265 VA Apparent Power Float. upper 16 bits 40267 Power Factor Float. upper 16 bits 40269 VOLTS Voltage, line to line Float. upper 16 bits 40271 VOLTS Voltage, line to neutral Float. upper 16 bits 40273 AMPS Current Float. upper 16 bits

Table above shows 7 consecutive floating point values (14 Modbus addresses).

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The command configuration to read these 7 floats would be setup as follows.

An array of 7 floats will need to be configured within the ControlLogix processor as shown.

And the following COP statement will copy the data from MCM.DATA.ReadData[0]-[13] into the array MCM_Float_Data[0]-[6].

The "Length" parameter is set to the number of Floating Point values that must be copied from the MCM.DATA.ReadData array.

4.4.3 Write Floats to Slave Device

To issue a Write command to Floating Point addresses, the following configuration can be used. Below is the Modbus Map for the slave device.

Value Description Type

A COP statement must be used to copy the data from floating point data tags within the ControlLogix processor, into the MCM.DATA.WriteData array used by the MVI56-MCM module. Below is an example.

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The length of this COP statement must now be 14. This will COP as many of the MCM_Float_Data values required to occupy the MCM.Data.WriteData array for a length of 14. This will take 7 registers, MCM_Float_Data[0]-[6], and place that data into MCM.DATA.WriteData[0]-[13].

The command to write all 7 floats (14 Modbus addresses) must be configured as follows.

The above command will take the data from MCM.DATA.WriteData[0]-[13] and write this information to the slave device node #1 addresses 40261 to 40274.

4.4.4 Read Floats with Single Modbus Register Address

(Enron/Daniel Float)

Some Modbus slave devices will utilize one Modbus address to store 32 bits of data. This is typically referred to as Enron or Daniel Floating Point.

A device that utilizes this addressing method may have the following Modbus Memory Map.

Address Data Type Parameter

47001 32 bit REAL Demand 47002 32 bit REAL Reactive Power 47003 32 bit REAL Apparent Power 47004 32 bit REAL Power Factor 47005 32 bit REAL Voltage: Line to Line 47006 32 bit REAL Voltage: Line to Neutral 47007 32 bit REAL Current

This type of device uses one Modbus address per floating point register. To read these values from the slave device, the following command can be setup within the module.

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Notice the count is now set to a value of 7. The reason for this is that because the slave device utilizes only 7 Modbus addresses, a count of 7 will cause the slave to respond with 14 registers (28 bytes) of information. This command will still occupy 14 register within the MCM.DATA.ReadData array, so make sure when you setup you IntAddress field for other Modbus Master commands, you make sure that the addresses 1000 to 1013 are not used for any other commands.

The COP statement for this type of data is the same as shown in Read Multiple Floating Point Registers (page 41).

4.4.5 Write to Enron/Daniel Floats

Issuing a Write command to Enron/Daniel Floats requires the use of the Float Flag and Float Start parameters within the configuration file.

This table provides the addresses that will be written to by the module.

Address Data Type Parameter

The Float Start and Float Flag parameters must be configured as shown.

The Float Flag alerts the module that it must look at the FloatStart parameter to know what DevAddress requires double the number of bytes to be issued on a write command.

1 With the above configuration, any DevAddress > 7000 is known to be floating

point data. Therefore a count of 1 will send 4 bytes of data, instead of the normal 2 bytes of data to a non Enron/Daniel floating point register.

2 First, Copy the floating point data from the ControlLogix processor into the

MCM.DATA.WriteData array used by the MVI56-MCM module. Below is an example.

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Here is the command that must be configured to write these 7 Floating Point values.

Based on the IntAddress and the configuration within the MCM.CONFIG.ModDef section for WriteStartReg and WriteRegCount, the data from the tag MCM.DATA.WriteData[0]-[6] will be written to Modbus addresses 47001 to 47007 of the slave device node #1.

Note: A swap code may be required to put the data in the proper format for the slave device.

4.5 Command Control and Event Command

Command Control and Event Command are features for the module in the master mode of operation that will allow the user to change the command execution based on some conditions in ladder. The module goes through the command list sequentially, for instance it looks at MCM.CONFIG.Port1MasterCmd[0], and then after completing that command will then execute MCM.CONFIG.Port1MasterCmd[1], then MCM.CONFIG.Port1MasterCmd[2], etc… Command Control and Event command give the user the ability to place a command directly to the top of the command queue, interrupting the regular command list execution.

Typically, this can be used to issue a reset to a device on a once a day basis, poll for end of hour data, or issue special commands on the startup of a process or the changing of a batch.

Because these special command blocks will interrupt the normal polling list, it is recommended that they are used sparingly, so that it does not interrupt your normal data transfer. Special consideration must be used to make sure that the data to be written to the device (on a Write command) has been placed into the module database.

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4.5.1 Command Control

Command Control will give you the ability to issue a command already defined in the master command list (but disabled) and enable that command for a single pass. Command Control has a distinct advantage over event command in that it will still return an error code for that command as setup in MCM.CONFIG.PortX.CmdErrPtr. Up to 6 commands may be enabled at the same time. The configuration of the command control is done using the following object in the ladder logic.

The following configuration will place 6 commands into the command queue. MCM.CONFIG.Port1MasterCmd[0]- MCM.CONFIG.Port1MasterCmd[5] will be

enabled with this configuration. Error codes for each individual command will be returned into the Error Status table.

Tag Value Description

TriggerCmdCntrl 1 1 will execute the command control NumberOfCommands 6 Number of commands per block PortNumber 1 MVI56-MCM port number (master) CommandIndex[0] to [5] 0 to 5

CmdsAddedToQueue

CmdControlBlockID

CmdCntrolPending

Stores the command index for command control block

Number of commands added to queue. This is the confirmation that the command control block has completed successfully

Temporary variable to calculate control block ID number

Aux. control command - prevents a second request before acknowledgement is received

Note: The ladder logic necessary for the successful e xecution of this block is contained in the _WriteControl ladder file, rung 4, and in the _ReadControl ladder file, rung 2.

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4.5.2 Event Command

Similar to command control, event command will also allow the user to add commands directly to the command queue, interrupting the normal polling sequence of the module. Unlike command control, event commands do not return an error code into the location defined by the MCM.CONFIG.PortX.CmdErrPtr value but Event Commands do not have to be defined in the regular command list.

Event command is a way of adding a command to the top of the MVI56-MCM modules command queue that is not defined within the command list.

Within an Event command block, the user is defining a Modbus command to add to the queue. Special consideration must be taken if the command is a write command, as the user must make sure that the block within the module that contains the data to write to the slave contains that latest value from the WriteData tag that corresponds to the Event Command.

Below is the structure of the EventCommand block.

Parameter Value Description

EventCmdTrigger 1 1 = trigger the event command EventCmdPending Used = EventCommand is executed once PortNumber 1 Module port # to send command out to SlaveAddress 1 Modbus Slave ID command to be issued to InternalDBAddress 1100

PointCount 10

SwapCode 0 Swap code used with command ModbusFunctionCode 3 FC 3 is read 4xxxx holding registers DeviceDBAddress 276

EventCmdStatusReturned Return value of 0 = Fail, 1 = Success EventBlockID

1100 will place the data read into MCM.DATA.ReadData[100]

Consecutive register/bits to read or write with the command

Address in the slave device to read. With FC3, DeviceDBAddress of 276, the module will read starting at address 40277 in the slave device

Block ID number for the module to recognize the event command, slave address, and port number to send the command out

The ladder logic used for the Event Command blocks is contained in _WriteControl rung 5 and _ReadControl rung 4 within the sample ladder file.

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Note: Event Command blocks can only send 1 command to the command queue per block. Note: Event Commands (like Command Control) will take pr iority over commands that are defined

in the normal command list.

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Configuration as a Modbus Slave MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

5 Configuration as a Modbus Slave

In This Chapter

 Overview ...............................................................................................49

 ModDef Settings.................................................................................... 50

 Read and Write Same Modbus Address (Pass Thru)............................54

 Slave Configuration ...............................................................................56

 Further clarification for some parameters in table above....................... 57

 Float Point Data Handling...................................................................... 57

5.1 Overview

When configuring the module as a slave, you will be providing whoever is programming the master side of the communications with a Modbus Memory Map.

Note: Utilizing the Sample Ladder Logic, the transfer of data is already done.

Information that is to be read by the Modbus Master device will be placed in the MCM.DATA.WriteData array as this will be pushed out to the module so that values from the ControlLogix processor can be read by the Modbus Master. Information that must be written to the ControlLogix processor from the Modbus Master device will be placed into the MCM.DATA.ReadData array.

To set up module as a Modbus Slave you must determine how much data you must transfer to and from the module, to the Modbus Master.

The sample ladder file is setup to transfer 600 16 bit registers in each direction. If more than that is required, please see Applications Requiring More Than 600 Registers of ReadData or WriteData (page 27).

Find out if the master can read from one Modbus address and write to another Modbus address, or, if the master must use the same address to read and write data points.

If the master must read and write to the exact same Modbus address, then a mode of operation called Pass Thru must be used.

This allows the MCM.DATA.WriteData array to be used for all data transfer to the master. Because the data transfer of the MVI56-MCM module cannot be bidirectional, in Pass Thru mode when a Modbus Write command is issued by the Master, the MVI module builds a special block of information. This block is then parsed by the ladder logic, and the value written from the Modbus Master is then updated in the MCM.DATA.WriteData array.

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Note: Pass thru should only be used when absolutely necessary, as there is a drawback to this mode of operation that is not present in the standard mode.

Because the module must wait on the ladder logic for the confirmation of the ladder receiving the new data from the master, if the master issues consecutive write commands, the second write command cannot be processed until the module has finished with the first command. This will cause the module to respond with an error code of 6 (module busy) on the Modbus network.

Note: It is recommended to use the module in the normal Slave mode of operation whenever possible. This configuration is covered first in the following.

5.2 ModDef Settings

To configure Modbus Slave mode of operation use the MCM.CONFIG.ModDef settings.

This section determines which of the MVI56-MCM module's 5000 registers of memory will be sent from the CLX processor out to the MVI module (WriteData) and which of the 5000 registers will be sent from the MVI module to the CLX processor (ReadData).

MCM.WriteData[0 to 599].

Value Description

WriteStartReg

WriteRegCnt

ReadStartReg

ReadRegCnt

BPFail

ErrStatPtr

Determines where in the 5000 register module memory to place the data obtained from the ControlLogix processor from the WriteData tags.

Sets how many registers of data the MVI module will request from the CLX processor. Because the module pages data in blocks of 200 words, this number should be evenly divisible by 200.

Determines where in the 5000 register module memory to begin obtaining data to present to the CLX processor in the ReadData tags.

Sets how many registers of data the MVI module will send to the CLX processor. This value should also be a multiple of 200.

Sets the consecutive number of backplane failures that will cause the module to stop communications on the Modbus network.

This parameter places the STATUS data into the database of the module. This information can be read be the Modbus master to know the status of the module.

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With the sample configuration, the following is the layout of the tags and addressing.

The sample configuration values set up the module database for WriteData[0 to

599] to be stored in the module memory at register 0 to 599, and ReadData[0 to 599] to be stored in the module memory at registers 1000 to 1599 like shown

above.

5.2.1 Modbus Memory Map

Based on the configuration described above, below is the default Modbus address for the module. Each register within the module can be accessed as a 0xxx bit address, 1xxxx bit address, 3xxxx register address, or 4xxxx register address.

MVI Address 0xxx 1xxxx 3xxxx 4xxxx Tag Address

0 0001 to 0016 10001 to 10016 30001 40001 WriteData[0] 1 0017 to 0032 10017 to 10032 30002 40002 WriteData[1] 2 0033 to 0048 10033 to 10048 30003 40003 WriteData[2] 3 0049 to 0064 10049 to 10064 30004 40004 WriteData[3] 4 0065 to 0080 10065 to 10080 30005 40005 WriteData[4] 5 0081 to 0096 10081 to 10096 30006 40006 WriteData[5] 6 0097 to 0112 10097 to 10112 30007 40007 WriteData[6] 7 0113 to 0128 10113 to 10128 30008 40008 WriteData[7] 8 0129 to 0144 10129 to 10144 30009 40009 WriteData[8] 9 0145 to 0160 10145 to 10160 30010 40010 WriteData[9] 10 0161 to 0176 10161 to 10176 30011 40011 WriteData[10] 50 0801 to 0816 10801 to 10816 30051 40051 WriteData[50]

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MVI Address 0xxx 1xxxx 3xxxx 4xxxx Tag Address

100 1601 to 1616 11601 to 11616 30101 40101 WriteData[100] 200 3201 to 3216 13201 to 13216 30201 40201 WriteData[200] 500 8001 to 8016 18001 to 18016 30501 40501 WriteData[500] 598 9569 to 9584 19569 to 19584 30599 40599 WriteData[598] 599 9585 to 9600 19585 to 19600 30600 40600 WriteData[599] 600 to 999 N/A N/A N/A N/A Reserved 1000 31001* 41001 ReadData[0] 1001 31002* 41002 ReadData[1] 1002 31003* 41003 ReadData[2] 1003 31004* 41004 ReadData[3] 1004 31005* 41005 ReadData[4] 1005 31006* 41006 ReadData[5] 1006 31007* 41007 ReadData[6] 1007 31008* 41008 ReadData[7] 1008 31009* 41009 ReadData[8] 1009 31010* 41010 ReadData[9] 1010 31011* 41011 ReadData[10] 1050 31051* 41051 ReadData[50] 1100 31101* 41101 ReadData[100] 1200 31201* 41201 ReadData[200] 1500 31501* 41501 ReadData[500] 1598 31599* 41599 ReadData[598] 1599 31600* 41600 ReadData[599]

The above addressing chart will work with many Modbus applications. Values listed in the ReadData array for 31001 to 31600 are shown with an * beside them.

Although these are valid addresses, they will not work in the application. The master must issue a Write command to the addresses that correspond to the ReadData array. For Modbus addresses 3xxxx these are considered Input registers, and a Modbus Master does not have a function code for this type of data.

5.2.2 Customizing the Memory Map

In some cases, the above memory map will not work for the application. Sometimes a master must read bits starting at address 0001, and also read a register starting at 40001. With the above memory map, this is not possible, as WriteData[0] is seen as both 0001 to 0016, and 40001. To accommodate this, you can customize the starting location within the module for each device using the parameters shown below.

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Parameter Value Description

BitInOffset 0

WordInOffset 10

OutOffset 1000 Defines the starting address within the module for 0xxx coils. HoldOffset 1010

Defines the starting address within the module for 1xxxx Modbus addressing. A value of 0 sets 10001 to 10016 as address 0 in the MVI56-MCM module.

Defines the starting address within the module memory for 3xxxx registers.

Defines the starting address within the module for 4xxxx addressing.

Based on the configuration described above for the ModDef section of the module and the values specified for the offset parameters, below is the Modbus addressing map for the module.

MVI Address 0xxx 1xxxx 3xxxx 4xxxx Tag Address

0 10001 to 10016 WriteData[0] 1 10017 to 10032 WriteData[1] 9 10145 to 10160 WriteData[9] 10 10161 to 10176 30001 WriteData[10] 11 10177 to 10192 30002 WriteData[11] 100 11601 to 11616 30091 WriteData[100] 200 13201 to 13216 30191 WriteData[200] 500 18001 to 18016 30491 WriteData[500] 598 19569 to 19584 30489 WriteData[598] 599 19585 to 19600 30490 WriteData[599] 600 to 999 N/A N/A N/A N/A Reserved 1000 0001 to 0016 ReadData[0] 1001 0017 to 0032 ReadData[1] 1009 0145 to 0160 ReadData[9] 1010 0161 to 0176 40001 ReadData[10] 1011 0177 to 0192 40002 ReadData[11] 1050 0801 to 0816 40041 ReadData[50] 1100 1601 to 1616 40091 ReadData[100] 1200 3201 to 3216 40191 ReadData[200] 1500 8001 to 8016 40491 ReadData[500] 1598 9569 to 9584 40589 ReadData[598] 1599 9585 to 9600 40590 ReadData[599]

With the offset parameters listed above, the Modbus Master could read from coils 10001 to 10176 using the tags MCM.DATA.WriteData[0]-[9]. The master could also read from address 30001 to 30490, and the data contained in those Modbus addresses would come from the tags MCM.DATA.WriteData[10]-[499] within the Control Logix program.

The master could then write to coils addressing 0001 to 0160 and this data would reside within the CLX program in tags MCM.DATA.ReadData[0]-[9]. The master could then write to registers using Modbus addresses 40001 to 40590, and this information would reside in addresses MCM.DATA.ReadData[10]-[599].

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Note: The offset parameter only set the starting location for the data. As shown above, if the master issues a Write command to address 40001, the data will go into the CLX processor at address MCM.DATA.ReadData[10].

Likewise, a Write To bit address 0161 will also change to address MCM.DATA.ReadData[10].0 within the program. Be careful not to overlap your data. You may want leave additional registers/bits unused to allow for future expansion in the program.

5.3 Read and Write Same Modbus Address (Pass Thru)

In some applications it is necessary for the Modbus Master to have the ability to read and write to the exact same Modbus address within the module. In all of the examples listed above this is not possible, as data can either be read from the WriteData array, or written to the ReadData array.

The mode of operation referred to as Pass Thru, will allow the Modbus Master to read and write the exact same Modbus address, using only the WriteData array. The basic theory of pass thru is that the ladder logic will constantly be updating values in the MVI56-MCM module memory using the WriteData array. When the master issues a Write command, the module will build a special block of data. This block of data is then presented to the ladder logic and then copied back into the WriteData array. Below is a chart showing the Pass Thru operation of the module.

Ladder logic for the pass thru operation is located in the subroutine _PassThru.

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Pass Thru should only be used when required. If a master issues a Write command to the module, the module must build a special block of information. Then, it waits for confirmation from the ladder logic that the block has been processed.

Note: If the module is waiting for the block to be processed by the ladder, and the master device issues another Write command, the module will return an Error Code of 6 (module busy). This results in the data written by the master not to be processed.

5.3.1 Pass Thru Coil Adjustment

The Sample Ladder Logic will only allow for the first 416 coils (26 registers) to be processed. This is due to the size of the Coil Array within the _UTIL.Passthru.MBCoil setup, and the Sample Ladder Logic. To increase this array the following steps must be performed.

1 Increase the Coil array under the User Defined data type of _CoilArray

(should be a value divisible by 32).

2 Change the ladder within _PassThru rung #2 to reflect this new change. This

must be changed in 2 places. First, the LES statement should be equal to the new array size.

3 The COP statement that copies the new status of the bits must have the

length changed to Equal to the number of bits defined in the array 416 bits in array / 16 = 26.

These changes are necessary for the proper operation of the logic when the ladder logic is processing the new write data from the master.

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5.4 Slave Configuration

Any parameters not mentioned in this section are not used when the module is configured as a Modbus Master. Parameters in BOLD are required for all applications as a slave.

Value Description Enabled Type

FloatFlag As a Slave, emulates Enron/Daniel style floats. See Float Point

FloatStart Register offset in message for floating data point. See Float Point

FloatOffset

Protocol Baudrate Sets the baud rate that the port will operate at. Valid values for this

Parity DataBits StopBits

RTSOn 0 to 65536 milliseconds delay before it issues the message RTSOff 0 to 65536 milliseconds delay after it issues the message MinResp milliseconds wait before response to the master UseCTS

SlaveID

BitInOffset Register value to offset address 10001 of the module memory WordInOffset Register value to offset address 30001 of the module memory OutOffset Register value to offset address 0001 of the module memory. HoldOffset Register value to offset address 40001 of the module memory InterCharacterDelay

1= enable port, 0 = disable port 1= Modbus slave port 2= Modbus slave port with pass thru (not recommended, see note

in Overview (page 49)). 3 = Modbus slave port with formatted pass thru and data values

swapped 4 = Modbus slave port with formatted pass thru (no swapping).

Data Handling (page 57) for more information.

Data Handling (page 57) for more information. Used to locate the floating point data into the module memory.

Refer to "Floating Point Support." 0 = Modbus RTU mode, 1 = Modbus ASCII mode

field are 110, 150, 300, 600, 1200, 4800, 9600, 19200, 384 or 3840 (for 38,400 baud), 576 or 5760 (for 57,600 baud) and 115,1152, or 11520 (for 115,200 baud)

0 = None, 1 = Odd, 2 = Even 8 = Modbus RTU mode, 8 or 7 = Modbus ASCII mode Valid values are 1 or 2

If the parameter is set to 0, the CTS line will not be monitored. If the parameter is set to 1, the CTS line will be monitored and must be high before the module will send data. This parameter is normally only required when half-duplex modems are used for communication (2-wire)

Valid values are 1 to 247

0 to 65535 milliseconds time between characters to signal end of message

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5.5 Further clarification for some parameters in table above.

Parameter Description

Type 2 =

3 =

4 =

InterCharacterDelay =

This allows for a write message to this slave to be passed through the module database, and go directly into the ladder logic. The module will set the MCM.CONTROL.BPLastRead value to 9996 and the Modbus write command will be handled by rung 0 in the _PassThru ladder file. This allows for an unparsed Modbus message to be moved into the tag location MBMsg[0 to 499]. Here you will need to parse out the data value and move it into the appropriate registers using the ladder logic (not recommended, available for backwards compatibility with older versions of firmware only).

This mode will allow for the same register to be read and written by a Modbus master device, and will also swap the bytes within the data value (most devices will need to use a value of 4).

This mode will also allow for the same register location to be read and written by the master device. Rungs 1, 2, and 3 in the _PassThru ladder file will handle this information.

Within Modbus RTU a character gap or quiet time on the line signals the end of the message. This is typically 3.5 character widths, as specified by the Modbus protocol. In some Radio or Modem applications, there may be more of a delay between characters.

5.6 Float Point Data Handling

In most applications, the use of floating point data requires no special handling. 1 Copy the data to and from the MVI module with a tag configured as a data

type REAL in the ControlLogix processor. Each floating point value will occupy 2 registers on the Modbus network.

Some master devices require the use of what is typically referred to as Enron or Daniel Float. These types of floats require one Modbus register for each float in the module memory. If your master is requiring this addressing, refer to the following section. For standard floating point data handling, the following is an example of copying 10 floats to the module.

2 First setup a tag within the CLX processor.

3 Then setup a COP statement within the main routine to copy this tag to the

MVI's MCM.DATA.WriteData array.

The length of the copy statement is determined by the Dest file size. To copy 10 floats from the MCM_Write_Floats array to the MCM.DATA.WriteData array, the length of the COP statement must be set to a value of 20.

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To copy data from the MVI module to a floating point tag within the CLX processor.

1 Setup a tag within the CLX processor as shown.

2 Then setup the COP statement to move data from the MCM.DATA.ReadData

array, and over to the new tag MCM_Read_Floats tag as shown here.

Once again, the COP statement will take as many of the Source elements required to fill the Dest tag for the length specified. Therefore the COP statement will take MCM.DATA.ReadData[0]-[19] to fill the MCM_Read_Floats[0]-[9].

5.6.1 Enron/Daniel Float Setup

Sometimes it is necessary for the module to emulate Enron or Daniel floating point addressing.

Copying the data to the MCM.DATA.WriteData array and from the MCM.DATA.ReadData array is the same as described in the section above. The main difference is the addressing of the module.

For instance, and Enron Float device is required to access address 47001 for floating point data, and each Modbus register would emulate a single float value (does not require 2 Modbus addresses for 1 float value).

A master device requiring this type of addressing, would require that for every count of 1, the MVI module responds to the request message with 4 bytes (1 32bit REAL) value.

To emulate this addressing, the module has the parameters MCM.CONFIG.PortX.FloatFlag, FloatStart, and FloatOffset.

Value Description

FloatFlag

FloatStart

FloatOffset

Tells the module to use the FloatStart and FloatOffset parameters listed below

Determines what starting address on the Modbus network to treat as floating point data. A value of 7000 will signal the module that address 47001 on the Modbus network is the starting location for Modbus floating point data. Every address will occupy 2 registers within the modules database

Determines what address within the module to associate the data from the FloatStart section to.

Here is a sample configuration for the module.

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With the above configuration, this would be the addressing for the module.

Module Address Mod bus Address Tag Address

100 47001 MCM.DATA.WriteData[100] 102 47002 MCM.DATA.WriteData[102] 104 47003 MCM.DATA.WriteData[104] 110 47006 MCM.DATA.WriteData[110] 120 47011 MCM.DATA.WriteData[120] 200 47051 MCM.DATA.WriteData[200] 300 47101 MCM.DATA.WriteData[300] 500 47201 MCM.DATA.WriteData[500]

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Verify Communications MVI56-MCM ♦ ControlLogix Platform Modbus Communication Module

6 Verify Communications

In This Chapter

 MVI56-MCM Status Data Definition as a Master ...................................61

 Verify Master Communications.............................................................. 62

 Verify Slave Communications................................................................ 66

You have followed our instructions and installed the software ladder, made changes, but you are not sure if you are communicating properly. This chapter provides an overview of how the MVI56-MCM module communicates using the MCM protocol.

6.1 MVI56-MCM Status Data Definition as a Master

This section contains a description of the members present in the MCM.STATUS object. This data is transferred from the module to the processor as part of each read block using the module's input image. Sample Ladder Logic will copy this information from the Local: x: I.Data {Offset} tag into the MCM.STATUS array.

Offset Content Description

202 Program Scan Count

203 to 204 Product Code These two registers contain the product code of "MCM". 205 to 206 Product Version

207 to 208 Operating System

209 to 210 Run Number

211

212

213

214 Port 1 Requests

215 Port 1 Responses

216 Port 1 Errors Sent

217

Port 1 Command List Requests

Port 1 Command List Response

Port 1 Command List Errors

Port 1 Errors Received

This value is incremented each time a complete program cycle occurs in the module.

These two registers contain the product version for the current running software.

These two registers contain the month and year values for the program operating system.

These two registers contain the run number value for the currently running software.

This field contains the number of requests made from this port to slave devices on the network.

This field contains the number of slave response messages received on the port.

This field contains the number of command errors processed on the port. These errors could be due to a bad response or command.

This field contains the total number of messages sent out of the port.

This field contains the total number of messages received on the port.

This field contains the total number of message errors sent out of the port.

This field contains the total number of message errors received on the port.

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Offset Content Description

218

219

220

221 Port 2 Requests

222 Port 2 Responses

223 Port 2 Errors Sent

224

225 Read Block Count

226 Write Block Count

227 Parse Block Count

228

229

230 Error Block Count

231 Port 1 Current Error

232 Port 1 Last Error

233 Port 2 Current Error

234 Port 2 Last Error

Port 2 Command List Requests

Port 2 Command List Response

Port 2 Command List Errors

Port 2 Errors Received

Command Event Block Count

Command Block Count

This field contains the number of requests made from this port to slave devices on the network.

This field contains the number of slave response messages received on the port.

This field contains the number of command errors processed on the port. These errors could be due to a bad response or command.

This field contains the total number of messages sent out the port.

This field contains the total number of messages received on the port.

This field contains the total number of message errors sent out the port.

This field contains the total number of message errors received on the port.

This field contains the total number of read blocks transferred from the module to the processor.

This field contains the total number of write blocks transferred from the module to the processor.

This field contains the total number of blocks successfully parsed that were received from the processor.

This field contains the total number of command event blocks received from the processor.

This field contains the total number of command blocks received from the processor.

This field contains the total number of block errors recognized by the module.

For a master port, this field contains the index of the currently executing command.

For a master port, this field contains the index of the command with the error.

For a master port, this field contains the index of the currently executing command.

For a master port, this field contains the index of the command with an error.

6.2 Verify Master Communications

The Modbus Master commands are setup, now it is time to verify that these commands are working correctly.

Within the MVI56-MCM module, there are a couple of ways of checking to see if the commands that have been configured in the previous location are working correctly.

The most common, and detailed method of checking the communications is using the MCM.CONFIG.PortX.CmdErrPtr parameter. This parameter will tell you the individual status of each command that is issued by the module. Another method is by checking the MCM.STATUS.PrtXErrs location for total commands issued, responses received, errors, and so on.

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6.2.1 Command Error Codes

The MVI56-MCM module will return an individual error code for every command configured within the MCM.CONFIG.PortXMasterCmd section. The location of these error codes are determined by the parameter MCM.CONFIG.PortX.CmdErrPtr. This parameter determines where in the module's 5000 register database the error codes for each command will be placed. The amount of error codes returned into the database is determined by the MCM.CONFIG.PortX.CmdCount parameter, therefore is the maximum number of commands have been selected (100), then 100 register will be placed into the module memory.

To be useful in the application, these error codes must be placed within the MCM.DATA.ReadData array.

Once again, the configuration in the MCM.CONFIG.ModDef section for ReadStartReg, and ReadRegCount determine which of the 5000 register will be presented to the Control Logix processor and placed in the tag MCM.DATA.ReadData array.

Based on the sample configuration values for ReadStartReg and ReadRegCnt, this will be addresses 1000 to 1599 of the module memory. Below are the sample configuration values.

Based on these values shown above, a good place for the MCM.CONFIG.PortX.CmdErrPtr is address 1500, as shown.

With the CmdErrPtr pointer set to address 1500 and the CmdCount set to a value of 100, this will place your Command Error Data at addresses 1500 to 1599 of the module memory, and because of the before mentioned configuration of the MCM.CONFIG.ModDef ReadStartReg and ReadRegCnt parameters, the command error data will be placed into the tags MCM.DATA.ReadData[500][599].

Each command setup in the MCM.CONFIG.PortX.MasterCmd will occupy one register within the ReadData array. Based on the sample configuration values, the table below is true.

Error Code for Command ReadData Location

MCM.CONFIG.Port1MasterCmd[0] MCM.DATA.ReadData[500] MCM.CONFIG.Port1MasterCmd[1] MCM.DATA.ReadData[501] MCM.CONFIG.Port1MasterCmd[2] MCM.DATA.ReadData[502] MCM.CONFIG.Port1MasterCmd[3] MCM.DATA.ReadData[503] MCM.CONFIG.Port1MasterCmd[4] MCM.DATA.ReadData[504] MCM.CONFIG.Port1MasterCmd[98] MCM.DATA.ReadData[598] MCM.CONFIG.Port1MasterCmd[99] MCM.DATA.ReadData[599]

To know where to look for the error data, you need to know what the individual error codes are.

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Below is a list of the error codes for the module:

Standard Modbus Protocol Errors

Code Description

1 Illegal Function 2 Illegal Data Address 3 Illegal Data Value 4 Failure in Associated Device 5 Acknowledge 6 Busy, Rejected Message

The "Standard Modbus Protocol Errors" are error codes that are being returned by the device itself. This means that the slave device understood the command, and replied back to that command with what is referred to as an Exception Response. The slave does not like something about the command that has been issued by the master.

The most common values are Error Code 2 and Error Code 3. Error Code 2 means that the module is trying to read an address in the device

that the slave does not recognize as being a valid address. This is typically caused by the slave device skipping some registers. If you have a slave device that has address 40001 to 40005, and 40007 to 40010, you cannot issue a read command for addresses 40001 to 40010 (function code 3, DevAddress 0, Count

10) because address 40006 is not a valid address for this slave. Try reading just one register, and see if the error code goes away. You may also

want to try adjusting your DevAddress -1, as some devices have a 1 offset. An Error Code of 3 is common on Modbus Write Commands (FC 5,6,15, or 16).

Typically, this is because you may be trying to write to a parameter that is configured as read only in the slave device, or the range of the data you are writing does not match the valid range for that device.

If you are getting one of the above listed error codes, this typically means that cabling, parameters such as baud rate, data bits, parity, and your wiring are all good, it is just that the slave device does not like the command being issued for some reason or another.

You may contact your slave device manufacturer or ProSoft Technical Support for more help with these types of error codes.

Module Communication Error Codes

Code Description

-1 CTS modem control line not set before transmit

-2 Timeout while transmitting message

-11 Timeout waiting for response after request 253 Incorrect slave address in response 254 Incorrect function code in response 255 Invalid CRC/LRC value in response

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"Module Communication Errors" are generated by the MVI56-MCM module, and are an indication that the communications with the slave device is not occurring correctly.

Error Code -11 indicates that the module is transmitting a message on the communications wire. However. it is not receiving a response from the addressed slave. This is typically an indication of a parameter mismatch (module is set for 9600 baud, slave is set for 19,200, parity is set to none, slave is expecting even, and so on), wiring problem (jumper on module is not set for correct position, or + and - lines on RS485 are switched), or the slave device is not set to the correct address (master command is sending command to slave 1 and the slave device is setup as device 10).

With a -11 error code, check all of the above parameters, wiring, and settings on the slave device. Also make sure that you toggle either the MCM.CONTROL.WarmBoot or ColdBoot bit to make sure that the values you have entered for within the MCM.CONFIG array are downloaded to the module. You can also cycle power to the module to perform a reboot and force the module to read the configuration from the ControlLogix processor.

Error codes of 253 to 255 are typically an indication of noise on RS485 lines. Make sure that proper RS485 cable is being used, and proper termination resistors are used on the line. If termination resistors are installed, you may want to remove them as they are usually on required on cable lengths of more than 1000 feet.

Command List Entry Errors

Code Description

-41 Invalid enable code

-42 Internal address > maximum address

-43 Invalid node address (< 0 or > 255)

-44 Count parameter set to 0

-45 Invalid function code

-46 Invalid swap code

The above error codes indicate that the module has detected an error when parsing the command.

For all commands that have not been configured (all parameters set to a value of

0) you will receive an error code of -44. To remove this error code, you can change your MCM.CONFIG.PortX.CmdCount parameter to the number of commands that are actually configured, and then toggle either the WarmBoot or ColdBoot bit to download this change to the MVI56-MCM module.

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6.2.2 MCM STATUS Data

Status information can also be obtained from the MVI56-MCM module by checking the MCM.STATUS.PrtXErrs location. Below is a sample.

If your system is working correctly, you will see CmdReq, CmdResp, Requests, and Responses all incrementing together. If you see that CmdErr is incrementing, you will need to see what command is in error (using the error code defined in the previous section) and based on the error code resolve the issue.

Note: This information is not as detailed as the individual error codes, but they can help to troubleshoot your application.

Also within the MCM.STATUS location is the parameters for Last Error and Previous Error, shown below.

This indicates the command index that last generated an error and does not indicate a command currently in error. In the above example, a value of 2 in Port1LastErr indicates that the last error was generated by MCM.Port1MasterCmd[2]. This does not indicate that this command is currently in error. The value in MCM.STATUS.Port1PreviousErr indicates that before MasterCmd[2] generated an error, MCM.Port1.MasterCmd[1] posted an error.

6.3 Verify Slave Communications

For verifying the communications to the module as a slave you can monitor the STATUS tags under the PrtXErrs section.

Below is an example.

The Requests field can be used to determine the number of request messages sent to the module as a slave, and the Responses section can be used to determine how many responses field can be used to determine how many times the module has responded to a request message from the Modbus master.

6.3.1 MVI56-MCM Status Data Definition as a Slave

Refer to MVI56-MCM Status Data Definition (page 119) for complete listing of Status information.

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7 Diagnostics and Troubleshooting

In This Chapter

 Reading Status Data from the Module .................................................. 67

 LED Status Indicators............................................................................ 80

The module provides information on diagnostics and troubleshooting in the following forms:

 Status data values are transferred from the module to the processor.  Data contained in the module can be viewed through the

Configuration/Debug port attached to a terminal emulator.

 LED status indicators on the front of the module provide information on the

module's status.

7.1 Reading Status Data from the Module

The MVI56-MCM module returns a 29-word Status Data block that can be used to determine the module's operating status. This data is located in the module's database at registers 6670 to 6698 and at the location specified in the configuration. This data is transferred to the ControlLogix processor continuously with each read block. For a complete listing of the status data object, refer to MVI56-MCM Status Data Definition (page 119).

7.1.1 The Configuration/Debug Menu

The Configuration and Debug menu for this module is arranged as a tree structure, with the Main Menu at the top of the tree, and one or more sub-menus for each menu command. The first menu you see when you connect to the module is the Main menu.

Because this is a text-based menu system, you enter commands by typing the command letter from your computer keyboard in the terminal application (for example, HyperTerminal). The module does not respond to mouse movements or clicks. The command executes as soon as you press the command letter — you do not need to press [Enter]. When you type a command letter, a new screen will be displayed in your terminal application.

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7.1.2 Required Hardware

You can connect directly from your computer's serial port to the serial port on the module to view configuration information and perform maintenance.

ProSoft Technology recommends the following minimum hardware to connect your computer to the module:

 80486 based processor (Pentium preferred)  1 megabyte of memory  At least one serial communications port available  A null modem serial cable.

7.1.3 Required Software

In order to send and receive data over the serial port (COM port) on your computer to the module, you must use a communication program (terminal emulator).

A simple communication program called HyperTerminal is pre-installed with recent versions of Microsoft Windows operating systems. If you are connecting from a machine running DOS, you must obtain and install a compatible communication program. The following table lists communication programs that have been tested by ProSoft Technology.

DOS ProComm, as well as several other terminal emulation programs Windows 3.1 Terminal Windows 95/98 HyperTerminal Windows NT/2000/XP HyperTerminal

7.1.4 Using the Configuration/Debug Port

To connect to the module's Configuration/Debug port:

1 Connect your computer to the module's port using a null modem cable. 2 Start the communication program on your computer and configure the

communication parameters with the following settings:

Baud Rate 57,600 Parity None Data Bits 8 Stop Bits 1 Software Handshaking None

3 Open the connection. When you are connected, press the [?] key on your

keyboard. If the system is set up properly, you will see a menu with the module name followed by a list of letters and the commands associated with them.

If there is no response from the module, follow these steps: 1 Verify that the null modem cable is connected properly between your

computer's serial port and the module. A regular serial cable will not work.

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2 Verify that RSLinx is not controlling the COM port. Refer to Disabling the

RSLinx Driver for the Com Port on the PC (page 105).

3 Verify that your communication software is using the correct settings for baud

rate, parity and handshaking.

4 On computers with more than one serial port, verify that your communication

program is connected to the same port that is connected to the module.

If you are still not able to establish a connection, you can contact ProSoft Technology Technical Support for further assistance.

Navigation

All of the sub-menus for this module contain commands to redisplay the menu or return to the previous menu. You can always return from a sub-menu to the next higher menu by pressing [M] on your keyboard.

The organization of the menu structure is represented in simplified form in the following illustration:

The remainder of this section shows you the menus available for this module, and briefly discusses the commands available to you.

Keystrokes

The keyboard commands on these menus are almost always non-case sensitive. You can enter most commands in lower case or capital letters.

The menus use a few special characters ([?], [-], [+], [@]) that must be entered exactly as shown. Some of these characters will require you to use the [Shift], [Ctrl] or [Alt] keys to enter them correctly. For example, on US English keyboards, enter the [?] command as [Shift][/].

Also, take care to distinguish capital letter [I] from lower case letter [l] (L) and number [1]; likewise for capital letter [O] and number [0]. Although these characters look nearly the same on the screen, they perform different actions on the module.

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7.1.5 Main Menu

When you first connect to the module from your computer, your terminal screen will be blank. To activate the main menu, press the [?] key on your computer's keyboard. If the module is connected properly, the following menu will appear on your terminal screen:

Caution: Some of the commands available to you from this menu ar e designed for advanced debugging and system testing only, and can cause the module to stop communicating with the processor or with other devices, resulting in potential data loss or other failures. Only use these commands if you are specifically directed to do so by ProSoft Technology Technical Support staff. Some of these command keys are not listed on the menu, but are active nevertheless. Please be careful when pressing keys so that you do not accidentally execute an unwanted command.

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Opening the Data Analyzer Menu

Press [A] to open the Data Analyzer Menu. Use this command to view all bytes of data transferred on each port. Both the transmitted and received data bytes are displayed. Refer to Data Analyzer for more information about this menu.

Important: When in analyzer mode, program execution will slow down. Only use this tool during a troubleshooting session. Before disconnecting from th e Config/Debug port, please press [S] to stop the data analyzer, and then press [M] to return to the main menu. This action will allow the module to resume its normal high speed operating mode.

Viewing Block Transfer Statistics

Press [B] from the Main Menu to view the Block Transfer Statistics screen. Use this command to display the configuration and statistics of the backplane

data transfer operations between the module and the processor. The information on this screen can help determine if there are communication problems between the processor and the module.

Tip: To determine the number of blocks transferred each second, mark the numbers displayed at a specific time. Then some seconds later activate the command again. Subtract the previous numbers from the current numbers and divide by the quantity of seconds passed between the two readings.

Viewing Module Configuration

Press [C] to view the Module Configuration screen. Use this command to display the current configuration and statistics for the

module.

Opening the Database Menu

Press [D] to open the Database View menu. Use this menu command to view the current contents of the module's database.

Opening the Command Error List Menu

Press [E] to open the Command Error List. This list consists of multiple pages of command list error/status data. Press [?] to view a list of commands available on this menu.

Viewing the Slave Status List (Port 1 and 2)

Press [O] (port 1) or [P] (port 2) to view the 256 slave status values associated with the ports. The slave status values are defined as follows:

0 = slave is not used, 1 = slave being actively polled, 2 = slave suspended and 3 = slave disabled.

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Viewing Version Information

Press [V] to view Version information for the module. Use this command to view the current version of the software for the module, as

well as other important values. You may be asked to provide this information when calling for technical support on the product.

Values at the bottom of the display are important in determining module operation. The Program Scan Counter value is incremented each time a module's program cycle is complete.

Tip: Repeat this command at one-second intervals to determine the frequency of program execution.

Warm Booting the Module

Press [W] from the Main Menu to warm boot (restart) the module. This command will cause the program to exit and reload, refreshing configuration parameters that must be set on program initialization. Only use this command if you must force the module to re-boot.

Transferring Module Configuration to the Processor

Press [Y] to transfer the module's configuration data to the processor. Ladder logic is required in the processor to receive and implement the updated configuration. You will be prompted to confirm the transfer.

If the operation is not successful, an error code will be returned.

Code Description

0 Transfer successful

-1 Error transferring module configuration data (block -9000)

-2 Error transferring device definition data (blocks -9100 to -9103)

-3 Error transferring master command list data (blocks -6000 to -6007)

After successful data transfer, the module will perform a warm-boot operation to read in the new data.

Communication Status (Ports 1 and 2)

Press [1] or [2] to view the communication status and statistics of the specified Modbus port. This information can be useful for troubleshooting network problems.

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Port Configuration (Ports 1 and 2)

Press [6] or [7] to view the configuration information for the selected Modbus port.

Exiting the Program

Press [Esc] to restart the module and force all drivers to be loaded. The module will use the configuration stored in the module's Flash ROM to configure the module.

7.1.6 Data Analyzer

The data analyzer mode allows you to view all bytes of data transferred on each port. Both the transmitted and received data bytes are displayed. Use of this feature is limited without a thorough understanding of the protocol.

Note: The Port selection commands on the Data Analyzer menu differs very slightly in different modules, but the functionality is basically the same. Use t he illustration above as a general guide only. Refer to the actual data analyzer menu on your module for the specific port commands to use. Important: When in analyzer mode, program execution will slow down. Only use this tool during a troubleshooting session. Before disconnecting from th e Config/Debug port, please press [S] to stop the data analyzer, and then press [M] to return to the main menu. This action will allow the module to resume its normal high speed operating mode.

Analyzing Data for the first application port

Press [1] to display I/O data for the first application port in the Data Analyzer. The following illustration shows an example of the Data Analyzer output.

Analyzing Data for the second application port

Press [2] to display I/O data for the second application port in the Data Analyzer.

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Displaying Timing Marks in the Data Analyzer

You can display timing marks for a variety of intervals in the data analyzer screen. These timing marks can help you determine communication-timing characteristics.

Key Interval

[5] 1 milliseconds ticks [6] 5 milliseconds ticks [7] 10 milliseconds ticks [8] 50 milliseconds ticks [9] 100 milliseconds ticks [0] Turn off timing marks

Removing Timing Marks in the Data Analyzer

Press [0] to turn off timing marks in the Data Analyzer screen.

Viewing Data in Hexadecimal Format

Press [H] to display the data on the current page in hexadecimal format.

Viewing Data in ASCII (Text) Format

Press [A] to display the data on the current page in ASCII format. This is useful for regions of the database that contain ASCII data.

Starting the Data Analyzer

Press [B] to start the data analyzer. After the key is pressed, all data transmitted and received on the currently selected port will be displayed. An example display is shown below:

The Data Analyzer displays the following special characters:

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Character Definition

[ ] Data enclosed in these characters represent data received on the port. < > Data enclosed in these characters represent data transmitted on the port. <R+> These characters are inserted when the RTS line is driven high on the port. <R-> These characters are inserted when the RTS line is dropped low on the port. <CS> These characters are displayed when the CTS line is recognized high. _TT_

These characters are displayed when the timing mark interval has been reached. This parameter is user defined.

Stopping the Data Analyzer

Press [S] to stop the data analyzer. Use this option to freeze the display so the data can be analyzed. To restart the analyzer, press [B].

Returning to the Main Menu

Press [M] to return to the Main Menu.

7.1.7 Data Analyzer Tips

From the main menu, press [A] for the "Data Analyzer". You should see the following text appear on the screen:

After the "Data Analyzer" mode has been selected, press [?] to view the Data Analyzer menu. You will see the following menu:

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From this menu, you can select the "Port", the "format", and the "ticks" that you can display the data in.

For most applications, HEX is the best format to view the data, and this does include ASCII based messages (because some characters will not display on HyperTerminal and by capturing the data in HEX, we can figure out what the corresponding ASCII characters are supposed to be).

The Tick value is a timing mark. The module will print a _TT for every xx milliseconds of no data on the line. Usually 10milliseconds is the best value to start with.

After you have selected the Port, Format, and Tick, we are now ready to start a capture of this data. The easiest way to do so is to go up to the top of you HyperTerminal window, and do a Transfer / Capture Text as shown below:

After selecting the above option, the following window will appear:

Next name the file, and select a directory to store the file in. In this example, we are creating a file ProSoft.txt and storing this file on our root C: drive. After you have done this, press the

Now you have everything that shows up on the HyperTerminal screen being logged to a file called ProSoft.txt. This is the file that you will then be able to email to ProSoft Technical Support to assist with issues on the communications network.

button.

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To begin the display of the communications data, you will then want to press 'B' to tell the module to start printing the communications traffic out on the debug port of the module. After you have pressed 'B', you should see something like the following:

The <R+> means that the module is transitioning the communications line to a transmit state.

All characters shown in <> brackets are characters being sent out by the module. The <R-> shows when the module is done transmitting data, and is now ready to

receive information back. And finally, all characters shown in the [ ] brackets is information being received

from another device by the module. After taking a minute or two of traffic capture, you will now want to stop the "Data

Analyzer". To do so, press the 'S' key, and you will then see the scrolling of the data stop.

When you have captured the data you want to save, open the Transfer menu and choose Capture Text. On the secondary menu, choose Stop.

You have now captured, and saved the file to your PC. This file can now be used in analyzing the communications traffic on the line, and assist in determining communication errors.

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7.1.8 Modbus Message Structure

Refer to Modbus Protocol Specification (page 127) for information on the structure of Modbus messages.

7.1.9 Modbus Database View

Press [D] to open the Modbus Database View menu. Use this command to view the module's internal database values. Press [?] to view a list of commands on this menu.

All data contained in the module's database is available for viewing using the commands. Refer to Modbus Protocol Specification (page 127) for information on the structure of Modbus messages. Each option available on the menu is discussed in the following topics.

Viewing Register Pages

To view sets of register pages, use the keys described below:

Command Description [0] [1] [2]

Display registers 0 to 99 Display registers 1000 to 1099 Display registers 2000 to 2099

And so on. The total number of register pages available to view depends on your module's configuration.

Redisplaying the Current Page

Press [S] to display the current page of data.

Moving Back Through 5 Pages of Registers

Press [-] from the Database View menu to skip back to the previous 500 registers of data.

Viewing the Previous 100 Registers of Data

Press [P] from the Database View menu to display the previous 100 registers of data.

Skipping 500 Registers of Data

Hold down [Shift] and press [=] to skip forward to the next 500 registers of data.

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Viewing the Next 100 Registers of Data

Press [N] from the Database View menu to select and display the next 100 registers of data.

Viewing Data in Decimal Format

Press [D] to display the data on the current page in decimal format.