Modbus®/TCP
Interface Configuration Quick Start
Trademark Notices
Document Number: 2000477 Rev G
Comtrol, DeviceMaster, and PortVision are registered trademarks of Comtrol Corporation.
Concept is a trademark of Schneider Electric.
Modbus is a registered trademark of Schneider Electric.
PLC is a registered trademark of Allen-Bradley Company, Inc.
Ethernet is a registered trademark of Digital Equipment Corporation, Intel, and Xerox Corporation.
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Other product names mentioned herein may be trademarks and/or registered trademarks of their respective
owners.
Seventh Edition, July 15, 2013
Copyright © 2005-2013. Comtrol Corporation.
All Rights Reserved.
Comtrol Corporation makes no representations or warranties with regard to the contents of this document or
to the suitability of the Comtrol product for any particular purpose. Specifications subject to change without
notice. Some software or features may not be available at the time of publication. Contact your reseller for
current product information.
Table of Contents
Overview...................................................................................................................................5
Comtrol Modbus Solutions .......................................................................................................................... 5
Locating the Latest Software and Documentation ............................................................................... 6
Modbus/TCP Installation Overview .......................................................................................................... 7
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters............................9
Prerequisites................................................................................................................................................... 9
Configuring Modbus/RTU Slaves ............................................................................................................. 10
Configuring Modbus/ASCII Slaves .......................................................................................................... 12
Configuring Modbus/RTU Master............................................................................................................ 14
Configuring Modbus/ASCII Master ......................................................................................................... 16
Configuring Read-Only Raw/ASCII Devices ..................................................................19
Prerequisites................................................................................................................................................. 19
Read-Only Raw/ASCII Serial Devices ..................................................................................................... 19
Embedded Web Page Configuration ........................................................................................................ 20
Modbus Raw Data Addressing ................................................................................................................. 25
Received Message Format ........................................................................................................................ 25
Read-Only Raw/ASCII Ethernet Devices ............................................................................................... 26
Embedded Web Page Configuration ........................................................................................................ 27
Modbus Addressing .................................................................................................................................. 33
Received Message Format ........................................................................................................................ 33
Configuring Read/Write Raw/ASCII Devices.................................................................35
Prerequisites................................................................................................................................................. 35
Read/Write Raw/ASCII Serial Devices.................................................................................................... 36
Embedded Web Page Configuration ........................................................................................................ 37
Modbus Addressing .................................................................................................................................. 46
Receive and Transmit Message Formats ................................................................................................ 46
Read/Write Raw/ASCII Ethernet Devices .............................................................................................. 47
Embedded Web Page Configuration ........................................................................................................ 48
Modbus Addressing .................................................................................................................................. 58
Receive and Transmit Message Formats ................................................................................................ 58
Filtering/Data Extraction Configuration .......................................................................61
PLC Filtering/Data Extraction ................................................................................................................. 63
Application Filtering/Data Extraction ................................................................................................... 65
Application Socket Configuration....................................................................................67
Alias Device ID Functionality ...........................................................................................71
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Table of Contents - iii
Table of Contents
Troubleshooting and Technical Support........................................................................75
Troubleshooting Checklist ....................................................................................................................... 75
General Troubleshooting........................................................................................................................... 76
Daisy-Chaining DeviceMaster UP 2E/4-Port Units .............................................................................. 77
Technical Support ....................................................................................................................................... 78
iv - Table of Contents DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Overview
This Quick Start is intended to help you quickly set-up serial or Ethernet devices. with the DeviceMaster UP.
You can use this document to locate software and installation documentation for the DeviceMaster UP to
quickly configure:
• Interfaces to serial Modbus/RTU and Modbus/ASCII slaves and masters
• Read-only devices such as barcode scanners and some RFID readers
• Read/write devices such as printers and some weigh scales
Comtrol Modbus Solutions
If you ordered the Modbus part number for your DeviceMaster UP, Modbus/TCP is loaded on the
DeviceMaster UP by default. You may want to review our other Modbus solutions to make sure that the
feature rich Modbus/TCP application is what you want to use. Optionally, Modbus Router or Modbus Server
may by more effective for your particular environment.
The Comtrol web site provides information about the differences between the three Modbus solutions:
• M
ODBUS/TCP
• M
ODBUS SERVER
• M
ODBUS ROUTER
In addition, the DeviceMaster UP product CD and ftp site also provide these documents for your reference.
The following links function if you are reading this document from the ftp site or CD.
Note: Optionally, open the CD and click Modbus. The main page (
links to these documents.
• Modbus Controller to Controller Communication
• Modbus Solution Examples
• Providing Read-Only Modbus Protection
• Resolving Modbus Device ID Conflicts
If Modbus Server or Modbus Router is a better solution, you can
corresponding documentation.
up_modbus_family_main.htm) provides
DOWNLOAD the appropriate firmware and
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Overview - 5
Overview
Modbus/TCP Installation Overview
The DeviceMaster UP follows these installation steps.
Note: The
1. C
2. I
NSTALL PORTVISION DX from the CD or download and install the latest version.
3. C
4. Depending on the DeviceMaster UP model, do the following:
• Models without Modbus/TCP loaded, you must install the software assembly (.msi) from the CD or
• Models with Modbus/TCP loaded on the DeviceMaster UP, you should check to see if a later version of
Note: Models that have Modbus/TCP loaded on the DeviceMaster UP are identified in PortVision DX and
5. I
F NECESSARY, UPLOAD the Modbus/TCP firmware into the DeviceMaster UP using PortVision DX.
6. Configure serial or Ethernet TCP/IP characteristics using the DeviceMaster UP embedded web page
(Server Configuration).
• Modbus/RTU serial slave devices (Page 10
• Modbus/ASCII serial slave devices (Page 12
• Modbus/RTU serial master (Page 14
• Modbus/ASCII serial master (Page 16
• Read-only raw/ASCII serial devices (Page 19
• Read-only raw/ASCII Ethernet devices (Page 26
• Read/write raw/ASCII serial devices (Page 36
• Read/write raw/ASCII Ethernet devices (Page 47
7. Optionally, the DeviceMaster UPModbus/TCP User Guide provides detailed information about each web
page.
8. You may want to reference the P
User Guide.
9. Optionally, reference the
10. C
11. Verify any Ethernet TCP/IP devices are connected to the same subnet as the DeviceMaster UP.
BLUE CAPITALIZED links jump to external documents, which work while viewing from the ftp site or
from the CD.
ONNECT THE DEVICEMASTER UP to the network.
ONFIGURE THE DEVICEMASTER UP network settings using PortVision DX.
download and install the latest file, which contains the Modbus/TCP firmware and supporting files
required for Step 5.
Modbus/TCP is available for installation. Check the Modbus/TCP version in PortVision DX against the
web site to see if a later version is available. Typically, you should download and install the latest .msi
file and upload the latest version, which may include updates or enhancements.
the DeviceMaster UP is labeled accordingly.
)
)
)
)
)
)
)
)
ROGRAMMING INTERFACE chapter in the DeviceMaster UP Modbus/TCP
EXAMPLE PLC PROGRAMS in the DeviceMaster UP Modbus/TCP User Guide.
ONNECT any serial device or devices.
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Overview - 7
Overview
Locating the Latest Software and Documentation
You can use the links in this table to check for updated software or documentation.
Software and Documentation FTP
Use PortVision DX to manage Comtrol Ethernet-attached devices to:
• Scan the network for attached devices
• View networked devices in real-time
• Access product-specific network settings configurations
• Assign IP addresses and network settings to one or multiple
devices
• Upload the latest firmware or Bootloader
PortVision DX
(Windows)
Modbus/TCP Firmware
DeviceMaster UP Hardware
Installation and Configuration
Guide
• Save and load configuration files
• Access DeviceMaster UP configuration web pages
• Access Telnet/SSH sessions
• Remotely reboot devices
• Download technical documentation
• Enable event logging to assist in monitoring and troubleshooting
• Create shortcuts to quickly access your favorite applications
• Organize devices into folders and create multiple views
• Enter notes about a folder or device
This is the application that may or may not have been loaded on the
DeviceMaster UP depending on the model that was ordered.
You may need to use PortVision DX to load this firmware.
This contains hardware installation, configuration information, and
connector information.
This includes using PortVision DX to configure the IP address and if
necessary, how to update the firmware.
Modbus/TCP Interface
Configuration Quick Start
This document with web interface configuration procedures.
The User Guide contains detailed information about the Modbus/TCP
(application) firmware, which includes additional information about
Modbus/TCP User Guide
the web configuration interface for Modbus/TCP.
It also discusses the example PLC programs that were installed on
your system and provides a Programming Interface chapter.
This Guide discusses the data extraction and filtering processes in the
DeviceMaster UP are designed to off load as much work as possible
DeviceMaster UP Filtering and
Data Extraction Reference
from the PLC and/or application and provide a very simple and easy to
use interface for standard RFID and barcode data.
Guide
This functionality and interface is designed to save dozens, possibly
hundreds of lines of ladder logic in a typical PLC program.
6 - Overview DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Overview
8 - Overview DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Modbus/RTU and Modbus/ASCII Slaves
Modbus Master(s) to Modbus Slave(s)
and Masters
For pure Modbus devices, the DeviceMaster UP supports:
• Modbus/RTU serial slaves
• Modbus ASCII serial slaves
• Modbus/RTU serial masters
• Modbus/ASCII serial masters
• Modbus/TCP masters
Note: All masters can communicate to all slaves.
Prerequisites
Before you can configure the serial ports for this mode, make sure that you have done the following:
• Installed the hardware
• Installed PortVision DX
• Configured the DeviceMaster UP IP address using PortVision DX
• If necessary, uploaded the latest Modbus/TCP firmware using PortVision DX
Note: The DeviceMaster UP provides an Modbus/TCP interface, which may or may not have the Modbus/
TCP firmware loaded (depending on the model you purchased). Models that have Modbus/TCP loaded
on the DeviceMaster UP are identified in PortVision DX and the DeviceMaster UP is labeled
accordingly.
If you need to perform any of these procedures or locate the latest files, see Overview
on Page 5.
Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 9
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
Configuring Modbus/RTU Slaves
Use the following procedure to configure a serial interface to Modbus/RTU slave(s).
1. Access the Server Configuration web page by entering the DeviceMaster UP IP address in your web
browser or by highlighting the DeviceMaster UP in PortVision DX and clicking Webpage.
Note: If the browser does not display the web page correctly, clear the browser history and refresh the
DeviceMaster UP web page.
2. Click the Serial Device Configuration link to open the Serial Device Configuration page.
3. Click Port N for the port you want to configure, where N is the port number.
4. If desired, provide a Serial Interface Name.
10 - Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
5. Set up the Serial Configuration for your device.
6. Configure the serial port for Modbus/RTU-to-Slaves operation. Under General Protocol Settings:
a. Set Serial Port Protocol to Modbus/RTU-to-Slaves.
b. Enable Discard Rx Packets With Errors.
c. Under Modbus Slave and Raw-Data Device Settings, set the Device Response Timeout value or leave at
the default.
d. 2/4-port models only
: Under Modbus Slaves Only, enable Lost Device Search Enable if you want the
DeviceMaster UP to search for a lost Modbus slave device on other Modbus/RTU and/or Modbus/
ASCII slave ports that also have this option enabled.
7. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
Note: If necessary, see Filtering/Data Extraction Configuration
on Page 61 or Application Socket
Configuration on Page 67 for additional configuration procedures.
Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 11
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
Configuring Modbus/ASCII Slaves
Use the following procedure to configure a serial interface to Modbus/ASCII slave(s).
1. Access the Server Configuration web page by entering the DeviceMaster UP IP address in your web
browser or by highlighting the DeviceMaster UP in PortVision DX and clicking Webpage.
Note: If the browser does not display the web page correctly, clear the browser history and refresh the
DeviceMaster UP web page.
2. Click the Serial Device Configuration option to open the Serial Device Configuration page.
3. Click Port N for the port you want to configure, where N is the port number.
4. If desired, provide a Serial Interface Name.
12 - Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
5. Set up the Serial Configuration for your device.
6. Configure the serial port for Modbus/ASCII-to-Slaves operation. Under General Protocol Settings:
a. Set Serial Port Protocol to Modbus/ASCII-to-Slaves.
b. Enable Discard Rx Packets With Errors.
c. Under Modbus Slave and Raw-Data Device Settings, set the Device Response Timeout value or leave at
the default.
d. 2/4-port models only: Under Modbus Slaves Only, enable Lost Device Search Enable if you want the
DeviceMaster UP to search for a lost Modbus slave device on other Modbus/RTU and/or Modbus/
ASCII slave ports that also have this option enabled.
7. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
Note: If necessary, see Filtering/Data Extraction Configuration
on Page 61 or Application Socket
Configuration on Page 67 for additional configuration procedures.
Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 13
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
Configuring Modbus/RTU Master
Use the following procedure to configure a serial interface to Modbus/RTU master.
1. Access the Server Configuration web page by entering the DeviceMaster UP IP address in your web
browser or by highlighting the DeviceMaster UP in PortVision DX and clicking Webpage.
Note: If the browser does not display the web page correctly, clear the browser history and refresh the
DeviceMaster UP web page.
2. Click the Serial Device Configuration option to open the Serial Device Configuration page.
3. Click Port N for the port you want to configure, where N is the port number.
4. If desired, provide a Serial Interface Name.
14 - Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
5. Set up the Serial Configuration for your device.
6. Configure the serial port for Modbus/RTU-to-Master operation. Under General Protocol Settings:
a. Set Serial Port Protocol to Modbus/RTU-to-Master.
b. Enable Discard Rx Packets With Errors.
7. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
Note: If necessary, see Filtering/Data Extraction Configuration
on Page 61 or Application Socket
Configuration on Page 67 for additional configuration procedures.
Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 15
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
Configuring Modbus/ASCII Master
Use the following procedure to configure a serial interface to Modbus/ASCII master.
1. Access the Server Configuration web page by entering the DeviceMaster UP IP address in your web
browser or by highlighting the DeviceMaster UP in PortVision DX and clicking Webpage.
Note: If the browser does not display the web page correctly, clear the browser history and refresh the
DeviceMaster UP web page.
2. Click the Serial Device Configuration option to open the Serial Device Configuration page.
3. Click Port N for the port you want to configure, where N is the port number.
4. If desired, provide a Serial Interface Name.
16 - Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
5. Set up the Serial Configuration for your device.
6. Configure the serial port for Modbus/ASCII-to-Master operation. Under General Protocol Settings:
a. Set Serial Port Protocol to Modbus/ASCII-to-Master.
b. Enable Discard Rx Packets With Errors.
7. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
Note: If necessary, see Filtering/Data Extraction Configuration
on Page 61 or Application Socket
Configuration on Page 67 for additional configuration procedures.
Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 17
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
18 - Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read-Only Raw/ASCII Devices
Serial Read-Only Device Communications
This chapter contains these subsections:
• Prerequisites (below)
• Read-Only Raw/ASCII Serial Devices (below)
•
Read-Only Raw/ASCII Ethernet Devices on Page 26
Prerequisites
Before you can configure the ports, make sure that you have done the following:
• Installed the hardware
• Installed PortVision DX
• Configured the DeviceMaster UP IP address using PortVision DX
• If necessary, uploaded the latest Modbus/TCP firmware using PortVision DX
Note: The DeviceMaster UP provides a Modbus/TCP interface, which may or may not have the Modbus/TCP
If you need to perform any of these procedures or locate the latest files, see
firmware loaded (depending on the model you purchased). Models that have Modbus/TCP loaded on
the DeviceMaster UP are identified in PortVision DX and the DeviceMaster UP is labeled accordingly.
Overview on Page 5.
Read-Only Raw/ASCII Serial Devices
Read-only raw/ASCII serial
devices use the Serial
Device Configuration page
to:
• Allow connections
between a serial device,
such as a barcode
scanner or RFID
reader, to PLC(s) and/
or application(s).
• Provide an optional
filtering mechanism for
string, RFID, and
barcode data.
The PLC and application
can both communicate to
the serial device, but they
cannot communicate
directly to each other.
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Configuring Read-Only Raw/ASCII Devices - 19
Configuring Read-Only Raw/ASCII Devices
Embedded Web Page Configuration
Use the following procedure to configure read-only raw/ASCII serial devices.
1. Access the Server Configuration web page by entering the DeviceMaster UP IP address in your web
browser or by highlighting the DeviceMaster UP in PortVision DX and clicking Webpage.
Note: If the browser does not display the web page correctly, clear the browser history and refresh the
DeviceMaster UP web page.
2. Click the Serial Device Configuration option to open the Serial Device Configuration page.
3. Click Port N for the port you want to configure, where N is the port number.
4. If desired, provide a Serial Interface Name.
20 - Configuring Read-Only Raw/ASCII Devices DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read-Only Raw/ASCII Devices
5. Set the Serial Configuration for your device.
6. Set the General Protocol Settings:
a. Set Serial Port Protocol to Raw-Data.
b. Enable Discard Rx Packets With Errors.
7. Set the Message Transfer mode, by setting the Raw-Data Message Transfer Mode to Data-Stream.
8. Set up the serial packet
identification (Serial Packet ID
Settings (Raw Data Only).
• Set the STX (Start of
transmission) Rx Detect in
decimal format.
• Set the ETX (End of
transmission) Rx Detect in
decimal format.
• Enable the S trip Rx STX/ETX
option if you do not want the
STX and ETX bytes returned
to the PLC or application(s).
Note: Refer to your device's User Manual for the Start and End of Transmission byte(s) settings. You may
also be able to use the Serial Interface Logs page to determine these settings.
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Configuring Read-Only Raw/ASCII Devices - 21
Configuring Read-Only Raw/ASCII Devices
You can use the Master Receive Transfer method only if your PLC can
operate as a Modbus/TCP slave, Modbus/RTU serial slave, or Modbus/
ASCII serial slave.
You can use the Slave Receive
Transfer method only if your PLC can operate as a Modbus/TCP master,
Modbus/RTU serial master, or Modbus/ASCII serial master.
9. Configure the Modbus/TCP and/or Serial Modbus Master Settings for your environment using one of the
following settings:
• Master Receive Transfer mode (recommended) writes data directly into the memory of a Modbus/
TCP slave or serial Modbus slave attached to this gateway. This requires the least amount of PLC
programming, requires the least amount of PLC overhead, and provides minimal latency.
Go to Step 10
on Page 23 to configure Master Receive Transfer mode.
• Slave Receive Transfer mode requires the PLC to poll for received data. This method is provided for
PLC programmers who prefer polling for data or those who have PLCs that can only operate in master
mode.
Go to Step 11
on Page 24 to configure Slave Receive Transfer mode.
22 - Configuring Read-Only Raw/ASCII Devices DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read-Only Raw/ASCII Devices
10. Master Receive Transfer Mode Only
Use the following procedure to configure Master Receive Transfer mode.
Under Serial Modbus Master and Modbus/TCP Settings (Raw-Data Only):
a. Set Rx (To PLC) Transfer Mode to Master (Write to PLC).
b. Set Tx (From PLC) Transfer Mode to either Slave (PLC Writes) or Off.
c. Set the Maximum Rx Data Packet Size to that of the largest expected receive data packet. For writing to
a Modbus/TCP slave or Modbus serial slave, this can be a maximum of 1,518 bytes.
d. Set the Oversized Rx Packet Handling to either Truncate or Drop, depending how you want to handle
oversized received packets.
e. Set Rx MS Byte First if you want to receive data most significant byte first.
f. Set the Disable Non-Filtered To PLC Rx Queue option if you only want to receive the last received data
packet. (If two or more packets are received during the Maximum PLC Update Rate time period, only
the last received data packet will be sent to the PLC.)
Under Modbus/TCP Master Rx/Tx Settings (Raw-Data Only):
g. Enter the PLC IP Address:
• For Modbus/TCP slaves, set the PLC IP Address to that of your PLC in xxx.xxx.xxx.xxx format.
• For Modbus/RTU or Modbus/ASCII serial slaves, set the PLC IP Address to that of this
DeviceMaster UP in xxx.xxx.xxx.xxx format.
Note: The Modbus serial slave must be attached to one of the serial ports on this DeviceMaster UP
chassis.
h. Enter the PLC Device ID:
• For Modbus/TCP slaves, set the PLC Device ID to that of your PLC. This is typically 1.
• For Modbus/RTU or Modbus/ASCII serial slaves, set the PLC Device ID to that of the serial slave
device.
Note: This must be a unique device id attached to this DeviceMaster UP chassis.
i. Set the PLC Rx Data Address to the PLC memory address where you want to place the received data
message. This address is Base 1, which means the address starts at 1 (or 400001 for some PLCs). If
your address range is Base 0, or starts at zero, you will need to add one to your address.
j. Set the Maximum PLC Update Rate to the fastest rate your PLC can reliably receive and process data.
This is typically longer than the scan rate. The default of 40 milliseconds is usually sufficient, but
your system may require a longer time period.
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G Configuring Read-Only Raw/ASCII Devices - 23
Configuring Read-Only Raw/ASCII Devices
k. Set the Use Maximum Sized Modbus Messages option if you are receiving messages over 196 bytes, your
PLC can receive messages larger than 200 bytes, and you want to decrease latency and network
usage.
Note: Go to Step 12
on Page 24 to complete configuration.
11. Slave Receive Transfer Mode Only:
Use the following procedure to configure Slave Receive Transfer mode.
Under Serial Modbus Master and Modbus/TCP Settings (Raw-Data Only):
a. Set Rx (To PLC) Transfer Mode to Slave (PLC Polls).
b. Set Tx (From PLC) Transfer Mode to either Slave (PLC Writes) or Off.
c. Set the Maximum Rx Data Packet Size to that of the largest expected receive data packet. This can be a
maximum of 246 bytes in Slave Rx mode.
d. Set the Oversized Rx Packet Handling to either Truncate or Drop, depending how you want to handle
oversized received packets.
e. Set Rx MS Byte First if you want to receive data most significant byte first.
f. Set the Disable Non-Filtered To PLC Rx Queue option if you only want to receive the last received data
packet. (If two or more packets are received between received data requests, only the last received
data packet will be returned.)
12. Set up the filtering/data extraction settings:
• If no filtering/data extraction is required, leave all filtering/data extraction settings to defaults (off).
• If filtering/data extraction is required, see
Filtering/Data Extraction Configuration on Page 61.
13. Set up the application socket interface settings:
• If no application socket interface is required, leave all application socket interface settings at defaults
and the application Enable option in not selected.
• If an application socket interface is required, see
Application Socket Configuration on Page 67.
14. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
24 - Configuring Read-Only Raw/ASCII Devices DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
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