Ethernet/IP option for the Catalyst and the Allen-Bradley RSLogix500 PLC platform

This technical note explains how to interface the RACO Catalyst Ethernet auto dialer directly to Ethernet networks. Specifically, this note will detail connectivity between the new Ethernet/IP option for the Catalyst and the Allen-Bradley RSLogix500 PLC platform.

Before We Begin, it is assumed that the reader of this tech note is already familiar with the basic operation and programming method of both the Catalyst product and Rockwell Automation software to include RSLinx Classic and RSLogix5000.

The Catalyst Ethernet supports one communication port, named NET 1. The Factory provided Ethernet cable attaches to the communication connector (ETHERNET) that is mounted on the bottom panel of the Catalyst chassis.

Catalyst Bottom PanelCatalyst_bottom_picture20percent

This Ethernet version of the Catalyst supports equally the ModbusTCP or the EtherNet/IP networks over the Ethernet port. The main purpose of connection to the Ethernet network is to get the PLC data natively instead of connection on other external network bridges.

Procedural Steps to Achieve Communications:


Click the Image next to the title to expand that section.

Image Setting the Ethernet/IP Address / Programming RSLogix500 Software


STEP #1 Identifying your Ethernet Network requirements

Most Ethernet/IP networks are comprised of a combination of PLC's, HMI's and workstation PC's running SCADA or similar software. Either Dynamic Host Configuration Protocol (DHCP) or static IP are accepted addressing schemes for Ethernet/IP networks. Where a DHCP server automatically assigns a IP address to a Host Name (device), and can change upon re-connection to the network, the static IP remains locked to the device. Consult your Network Administrator for your preferred scheme. Either of which is offered with the Catalyst.

It is recommended to have a single connection write to the Catalyst. Although up to 16 connections are possible, they would be writing to the same address(s) and may be cause for unnecessary confusion. We recommend a single write connection however, up to 16 connections may listen/read from the Catalyst.

If your existing network uses more than one controller to provide alarm notification, we would encourage messaging all alarms to a single controller (data concentrator) that would, in turn, connect to the Catalyst.

STEP #2 Setting the Ethernet/IP address within the Catalyst RACO IPconfig tool

Make sure each node on the network has a unique IP address. The IP settings of the Catalyst EtherNet/IP modules can be configured in various ways. It is recommended to use the “Device Settings” menu that appear in the Alarmware software and follow the steps that are highlighted in the following image below.

1. Click the Protocol tab
2. Select Ethernet from the drop down menu
3. Run the RACO IPConfig application by selecting the “Ethernet Configuration” Button



Figure #1 Alarmware Device Settings Dialog

Once the program is launched it will automatically scan your Ethernet port looking for RACO Ethernet auto-dialers.

Click the SCAN button to re-scan the network. The RACO IPconfig tool can be used to configure the IP settings of all RACO EtherNet/IP modules. Also, it is able to locate all the RACO Ethernet auto dialers in the network.

There is no need to have the auto dialers in the same subnet to be discovered. The settings can be configured manually or the DHCP function can be used. For the RACO Catalyst Ethernet modules DHCP is activated by default. To change the settings manually, double click on the desired module and enter the desired IP-settings as seen below.


Figure #2 RACO IPConfig Tool


                 Figure #3 Configure IP Settings

Ensure each node on the network has a unique IP address.

EDS Hardware Installation tool

An Electronic Data Sheet (EDS) file, that identifies your RACO Auto dialer within Rockwell RSLinx environment, needs to be installed onto your system via the EDS Hardware Installation Tool. This install utility would typically be located under your RSLinx/Tools directory.


Figure #4 EDS Hardware Installation Tool Menu

Once the EDS Hardware Installation Tool has been launched, select the path/location of your RACO EDS file. This file was included within your Alarmware CD that was shipped with the Catalyst, The EDS file should be copied over to your system and installed via the EDS Hardware Installation tool illustrated below. The file is located on the CD in the \RACO\Alarmware20 folder


Figure #5 EDS Hardware Installation Dialog

STEP #3 Confirming Ethernet connections with all applicable devices

Command Prompt (CMD) Via your operating system, launch CMD.exe. You should be able to PING the RACO devices on the network. Make sure your PC's IP address shares the same SUBNET. A successful response from your RACO auto-dialer would appear similar to the photo below.


Figure #6 Command Prompt

RSLinx Classic Following confirmation of RACO products on your network via the command prompt, it would be a good practice to next open your RSLinx Classic software and view the online status via RSWho. This technical note assumes that one is familiar with RSLinx Classic software and can configure the appropriate driver to suit. Via RSLinx Classic you should now be able to observe the RACO auto-dialer as active within the RSWho form.


Figure #7 RSLinx Classic Pro Software

Step #4 Programming RSLogix500 software to communicate with the Catalyst

Ethernet Configuration within the RSLogix500 Environment Embedded within the SLC 5/05 processor, on Channel 1 is an Ethernet port. This port will support the CIP protocol via the EtherNet/IP Explicit Message Instruction. (EEM) The EEM instruction will compile a CIP type packet of data and transmit/receive to the desired IP destination.

Configuration of the EtherNet/IP Explicit Message Instruction. (EEM) This instruction can be used with any SLC 5/05 processor at OS firmware level Series C, FRN 10 or higher. The EEM Instruction is located under the ”Input/Output” tab of the "Tab Instruction Bar". Drop one onto your ladder as an output and assign a block of Integer Register values. NOTE: To READ and WRITE data the EEM instruction must be triggered. (i.e. the rung must go high)

In our example, once triggered we've enabled the EEM instruction for 100ms provided no instruction error.


Figure #8 Ethernet IP Explicit Message Instruction (EEM)

Once the Control Block of Integer Registers has been assigned, press ENTER. This will launch the EEM Configuration dialog, see below.

The dialog will appear with the GENERAL tab open. It is here we assign the messaging details. The RSLogix500 platform via the EEM instruction will communicate to the Catalyst via Explicit messaging. Every Integer array or block READ or WRITE will require its own EEM instruction.

For data READ from the Catalyst, define the HEX fields as follows:


Once all fields in the GENERAL tab have been completed, open the MULTI-HOP tab and enter the Catalyst's IP as defined with the RACO IPconfig tool, under the "ToAddress" field. Then close the dialog. Download or if online, Assemble your edits and you are ready to test.


Figure #10 EEM - Multi Hop Tab


Image Modbus Protocol Overview

STEP #5 Modbus Protocol

Modbus RTU is a serial communications protocol originally published by Modicon, for use with their programmable logic controllers. Due to its inherent ease of deployment and maintenance, the fact that it is royalty free and well suited to a variety of applications it has earned its place as a communication standard amongst the Industrial Control community.


Figure #11 Modbus Address Table

The above table illustrates the Modbus data file convention within the Catalyst. These Modbus Register Addresses map to integer files defined within the Block of TAGs defined in the EtherNet/IP Explicit Message Instruction. (EEM)

It is important to recognize the differences when addressing coils and registers. The Modbus convention allows for the mapping of various Modbus type registers to unique internal memory locations within the PLC.

For Example:

  • 30001 will go to a particular read-only input register (e.g. temperature), whereas 40001 will go to a different read/write holding register (e.g. set point).
  • RACO auto dialers do not work this way. All the different areas are mapped on top of one another.

For Example:

  • 30001 holds the same value as 40001.
  • Coil 00001 holds the same value as the first bit of 30001 or 40001
  • Registers 1-30 hold read only input data
  • Coils 1-480 (16-bit*30) hold input data
  • Coils 16385 (16-bit*1025) – 16865 (+16*bit*30) hold read/write output data

This allows flexibility to look at data as input registers, holding registers, coils, etc., as many Modbus masters don’t have all functions implemented.


Since both Output Register (4xxxx) and Holding Register (5xxxx) data types use the same data area at the RACO end, the Holding Register (5xxxxx) uses two consecutive 16 bit addresses that are interpreted as a 32 bit floating point number. (i.e. 5xxxx & 5xxxx+1)

Not unlike the Holding Register, the Output Register (4xxxx) also reserves two consecutive 16 bit words however the extended word is left blank.

Similarly when addressing the input register (3xxxx), allow for two consecutive 16 bit words, keeping in mind the extended word is reserved but not used.

Hence, consecutive addressing of both Input and Output Registers will appear as follows:

For example, first Input Register address point 30001, 2nd address point 30003, 3rd address point 30005, etc.

Image Communication Registers

In order to better support the new Ethernet/IP card, we have provided the addition of a Communication Health Bit.

As this is a new option, it has yet to be included within the Catalyst User's Manual. This can be easily configured to monitor Ethernet connectivity.

Should the Catalyst lose it's connection to the Ethernet/IP master, the health byte 40124 will go from 0 to 256 (i.e. REGISTER #124, BIT #8) or the bit 01992 will go from 0 to 1.

Normally LOW, should loss of communications occur, the bit will go HIGH. It is recommended to ALARM when the state goes HIGH.

To enable the loss of communication alarm, program the Catalyst to ALARM when HIGH address 01992. Assign this ALARM to any available channel. (i.e. Channel 56)
Program Channel 56 SNA: 1*2*01992 (channel 56 reads address 01992) , Alarm on 1 Raw Value, 0 Reported as '0.'

You may choose any available channel for this function (shown here using channel 56). We recommend using a channel near the end, i.e., 56, 96 or 256 depending on your model.

Note that Normal means actually talking to the PLC. You would get an alarm if you are plugged into the Ethernet, but the PLC is not communicating, or if you are not plugged into the Ethernet.
Note also that this bit will use one of the available channels on the Catalyst (in this case channel 56).


To announce communication interruption alarms; Make sure to record alarm messages by following ‘Message Recording and Reviewing” Starting on page 7-47 of the main Catalyst manual.

Image Configure Remote Channels / Tag Monitoring

Step #7 Assign addresses to a Remote Channel (Digital)

To set up the Catalyst to read the tag that has been mapped to Modbus bit address 10001 and assign it to remote channel. Select the remote channel you wish to edit.

Then use SNA 1*2*0XXXX where XXXX is the bit address.


  • 1*2*10001 for Modbus address 10001
  • Set the alarm condition under channel settings, Alarm Violation Criteria

Assign addresses to a Remote Channel (Analog)

  • To set up the Catalyst to read the tag that has been mapped to Modbus analog address 30001 and assign it to remote channel. Select the remote channel you wish to edit.
  • Then use SNA 1*2*40XXX where XXX is the 16-bit register
  • Example: 1*2*30101 for Modbus register 30101
  • Set the alarm condition under channel settings, Alarm Violation Criteria


  • You may reference Catalyst user manual (Starting on page 7-65) to complete this step.
  • These are examples to assign alarms conditions to channel ZZ
  • If Channel ZZ is configured as a bit it can have a value of 1 or 0 (Ref Main Manual page 7-65)
  • If Channel ZZ is configured as an analog, the valid operating range is 0 to 65,535

STEP #8 Tag Monitoring

When ONLINE and in RUN mode, PLC tags defined under the general tab of the EEM instruction will contain the data shared with the Catalyst. The example below shows data register block defined to WRITE digital bits to the Catalyst.


Figure #12 EEM Write Assemby

Bits N12:10/0 through to N12:11/15 can be set according to your Remote Channel settings in the Catalyst.


Figure #13 N12 Data Table

It is good practice to test all remote channel connectivity to the Catalyst via the Controller TAG monitor window.
Select any ANALOG or BIT value, edit and verify the appropriate ALARM response via the Catalyst.
Alarming should occur according to your remote channel settings within the Catalyst.

Image Quick Start

STEP #9 Quick Start

Step #1 - Set up Catalyst

  • Install Alarmware
  • Connect to the Alarmware port of the Catalyst
  • Add a new RTU within Alarmware, using the corresponding model number
  • Select that RTU and click the “Connect COM Port” button
  • Go to the Configuration/Devices/Protocol menu. MBMaster should show 9600 baud, 1 stop bit, even parity, and Catalyst node 1.

(Note that although some Catalyst parameters can be configured with the front panel keys, Catalyst Ethernet will need to be configured with Alarmware)

Step #2 - Set up Ethernet side of Catalyst

  • Plug Ethernet cable into Ethernet outlet
  • - Select protocol Ethernet, then click “Ethernet Configuration.” This will bring up RACO IPConfig (which must be in the same directory as Alarmware).
  • - Use Raco IPConfig tool to determine current IP of Catalyst Ethernet card, and change it if necessary. You’ll want the Catalyst Ethernet to be on the same net as the PLC.
  • Example: PLC is at , then Catalyst Ethernet might be

Step #3 - Set up PLC

  • Configure the addressing tags and communication in RSLogix500

Step #4 - Set up Network remote channels

  • Channels are set up under Configuration/Channel Settings
  • Example for a Remote Digital bit: 1*2*10001 for Modbus address 10001
  • Set the alarm condition under channel settings, Alarm Violation Criteria Saved: 2014-06-18
  • Filename: Catalyst Ethernet Addendum 1 1 V1_5 released RACO Manufacturing and Engineering