782-JDM DeviceNet™-ModBus Gateway User’s Manual Western Reserve Controls, Inc.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual Although every effort has been made to insure the accuracy of this document, all information is subject to change without notice. WRC takes no liability for any errors in this document or for direct, indirect, incidental or consequential damage resulting from the use of this manual. Document PUB 24.0 Rev 2.11 July 2011 Copyright © 1999-2011 WRC Western Reserve Controls, Inc.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual TABLE OF CONTENTS 1 OVERVIEW........................................................................................................................................................3 1.1 FEATURES .........................................................................................................................................................4 1.1 PRODUCT FAMILY SELECTION .......................................................................
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual LIST OF TABLES TABLE 1-1 DATA MESSAGE OPTIONS ............................................................................................................................6 TABLE 2-1 ADDRESS SELECTION ...................................................................................................................................8 TABLE 2-2 RS-232/485 CONNECTOR SIGNALS .................................................................................
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 1 Overview The 1782-JDM is a family of DeviceNet-to-ModBus interfaces that allows you to easily connect and integrate a ModBus-capable device into a DeviceNet system. The ModBus device’s real-time data is read and written as I/O by the DeviceNet Master via Polled I/O. The devices set up parameters, if any, can be read and written with the Explicit Messaging technique.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 1.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 1.3 JDM Operational Philosophy A Modbus network system consists of a single MB Master and one or more MB Slave Devices. The JDM, as the proxy to the DeviceNet Master, becomes the ModBus master. All other devices on the Modbus link must be defined as Slaves. - The JDM is a Slave on the DeviceNet bus - The JDM communicates on DN with the DN Master using the Polled I/O technique for transmitting and receiving MB data.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual master. The DeviceNet Master can receive and send data to and from the JDM via the methods described in this section. It interprets messages received from the DeviceNet connection, and if it is a ModBus message, reformats and sends it to the ModBus device. Likewise, it accepts and interprets responses from the ModBus device, which are reformatted and passed back to the DeviceNet system as required. The JDM has one DeviceNet address.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual command and number of register data desired. The command response from the ModBus device is returned from the JDM to the DeviceNet master in response to a poll command. The DeviceNet response data includes a record number byte and a status byte, which contains a “waiting” bit. The DeviceNet response will be valid when both the record number matches the one sent in the Poll Command and the waiting bit (bit 7) is reset to zero (0). 1.4.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 2 Quick Start To quickly and easily install your JDM in your DeviceNet system, follow the instructions below. For more details, see Section 2.3. To Install and Establish DeviceNet Communications 1. Connect the DeviceNet cable to the 5-pin plug (supplied) according to DeviceNet cable wiring specifications. 2. Make sure that the DeviceNet network is terminated properly. (See Section 3.5 below.) 3.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 2. Switch setting changes do NOT take effect until the device is reset with either a device RESET command (to the class 1 Identity object) or a power cycle. 2.2 How to Change the DeviceNet Baud Rate 1. The baud rate defaults to autobaud.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 2.4 How to Read ModBus Device Input Data 1. Set up the poll input data field size in your Master’s scan table to be equal to or greater than the number of bytes required for the largest ModBus message received from your device(s). (Default size is 48 bytes). 2. Set up a Poll Connection (Allocate Connection Instance 2) to the 1782-JDM from the Master. 3.
Western Reserve Controls PUB 24.0 • 1782-JDM User’s Manual rd 3 Register data (2 byes) 2.5 How to Write ModBus Device Output Data 1. Configure the port to send output data by setting the size of the poll output buffer at the Master to reflect the number of output bytes that will be sent to the ModBus device (default is 48 bytes). 2.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 01hex Invalid ModBus format; for example bad length, no colon in response, etc. 10hex Invalid ModBus data from DeviceNet master 80hex Waiting bit; JDM waiting for a response from the ModBus device.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 3 Hardware Installation and Configuration 3.1 Overview The ASCII contains two LEDs to indicate the status of the device and the status of the network. The device can be connected to the main DeviceNet trunk line or to a drop line via screw terminations on the open, pluggable 5-pin DeviceNet connector supplied with your unit.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 3.2 LED Operation An ASCII Multiplexer has two LEDs that provide visual status information to the user about the product and the DeviceNet network. See Table 3-1 and Table 3-2. Table 3-1 Module Status LED (labeled MS) LED State Module Status Meaning OFF No Power There is no power through DeviceNet. Green Device Operational ASCII is operating normally.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 3.3 Serial Port Connectors Your ModBus device(s) are connected to the JDM via 3-wire or 5-wire communications cable. See your ModBus device User Manual for details on the specific connection.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 3.5 DeviceNet Network Configuration DeviceNet specifications provide for a maximum network distances for the main trunk line and drop lines, depending upon the baud rate used on the network. They are: Table 3-5 Network Maximum Lengths Trunk Line Length Drop Length Maximum Distance Maximum Cumulative Baud Rate Meters Feet Meters Feet Meters Feet 125k baud 5OO m 164O ft 6m 2O ft 156 m 512 ft.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 3.5.1 DeviceNet Network Termination A DeviceNet system must be terminated at each end of the trunk line. The host controller and the last JDM or other DeviceNet device on the network must always be terminated to eliminate reflections, even if only two nodes are present.
Western Reserve Controls PUB 24.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 4 Software Configuration The ASCII Multiplexer is software-configured for several parameters. Table 4-1 below defines the legal values and the default values for the device address (referred to as the device’s MacID), baud rate and ASCII configuration selections available.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual Table 4-1 Configuration Parameters Parameter Param.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 2. Rx Data Length: Maximum number of bytes expected from the remote ModBus device. Note that the DeviceNet produce length will read this length + 2. 3. Tx Data Length: Maximum number of bytes to be sent to the remote ModBus device. Note that the DeviceNet consume length will read this length + 1. 4. ModBus Baud rate: The communications speed of the RS232 or RS485 link. 5.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 5 DeviceNet I/O Assembly Formats The following tables define the format of the DeviceNet data sent to and received from the JDM. The exact format of the output and input data that is sent from and received at your DeviceNet master is defined by the ModBus command used. The following tables provide the general format and illustrate the differences between the ASCII and RTU modes.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual Table 5-2 I/O Assembly Object Instance 2 Data Format – Short Command w/o Fragmentation Byte (Offset value) 0 1 2 3 4 5 6 7 Data Record number Length Address Command Data www – LSB Data www – MSB Data xxx – LSB Data xxx – MSB 5.2 Input Data, ModBus Response The exact format of the input data that is received at your DeviceNet master is defined by the ModBus command used.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 6 General Specifications Product: 1782-JDM – DeviceNet-to-ModBus Gateway o 1782-JDC-1, Isolated RS-232 o o 1782-JDC-2, Isolated RS-485 1782-JDC-4, Isolated RS-422/485 Description: Communications gateway between a ModBus device over an RS232/422/485 network and a DeviceNet network.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual Network Status: green/red bi-color LED Network Termination: External terminating resistor (optional per user system configuration) Serial port: Baud rate: 1200, 2400, 4800, 9600, 19.2k, 38.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 7 ModBus Protocol Complete details about the ModBus protocol can be found in the Modbus Organization web site: http://www.modbus.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual PRELIMINARY 8 Troubleshooting This section identifies some of the common problem observed when commissioning or operating a DeviceNet and JDM. Problem: JDM powers up. The module LED flashes green. The network LED is OFF. JDM does not communicate over the network. Possible Solution: The JDM is in Autobaud mode, and is waiting for a few messages to cross the network so it may determine the baud rate setting.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual Problem: JDM operates on DeviceNet but does not seem to handle ModBus activity. Possible Solutions: 1. Check the RX and TX LEDs on the JDM. A successful transmission will appear as: • Brief TX LED flash • Brief RX LED flash • Both LEDs off If the sequence does not appear as this, then there is a wiring problem. 2. If this is an RS485 link, make sure it is properly terminated. (121ohm resistor at each end.) 3.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 9 Accessories and Other WRC Products The following components can be used with a 1782-JDM-x for replacements or spare parts, or as complementary devices as a part of your DeviceNet system.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual 10 Frequently Asked Questions 1. Where is the 1782-JDMx gateway User’s Manual located? The WRC 1782-JDMx product User’s Manuals are available from our web site Support -> Technical Data http://wrcakron.com/data.html. 2.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual to use a DeviceNet software configuration tool. Many of these tools have EDS readers, which make the editing process easier. 10. Does a 1782-JDMx gateway provide electrical isolation? Yes, a 1782-JDMx gateway provides 1000V network electrical isolation. 11. What are the currently available 1782-JDMx gateway models? 1782-JDM-1: Isolated RS232 Interface 1782-JDM-2: Isolated RS485 Interface 1782-JDM-4: Isolated RS422 Interface 12.
Western Reserve Controls PUB 24.0 1782-JDM User’s Manual will need to turn the PAD Mode ON. This parameter should be checked if the 1782-JDMx will not stay connected due to an IO size error. 17. What should my master device logic be doing to see if new data is present in a poll message? The Master program logic should be looking at the Receive Record Number and comparing it with the last stored record number to monitor new data arrival in Immediate (Non-Handshake) Mode.
