Knowledge Base / Protocols / DeviceNet

1782-JDCx Frequently Asked Questions

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1.    1.     Where are the 1782-JDCx gateway User’s Manuals located?

The WRC product User’s Manuals are available from our web site Support -> Technical Data

2.       What are the 1782-JDCx gateways and why should I consider purchasing one for my DeviceNet network?

The 1782-JDCx gateways are communications adapter devices that provide you with a flexible DeviceNet interface to a wide variety of ASCII devices. The JDCx models allow you to easily and conveniently connect and integrate peripheral products with either RS-232, RS-485 or RS-422 serial ports into a DeviceNet system, enabling you to select just the right peripheral device for your application without limiting your selection to DeviceNet-cable devices only.


3.       How can I change the DeviceNet MAC ID of my 1782-JDCx?

The address of the 1782-JDCx will come preset from the factory for address 63. You may change the address using the bank of 6 DIP switches on the unit: they can be set to any address from 0 to 63 in binary (111111=address 63). The MACID or address will not change if the switches are moved while the device is powered; power must be removed and reapplied when a new switch setting and MAC ID are desired or a device reset command must be issued.


4.       What electrical connections are required for a 1782-JDCx gateway?

DeviceNet Cable Connection:

1, 5-pin pluggable header (male, Phoenix Contact MSTBA 2.5/5-G-5.08/AU or equivalent)


Serial Cable Connection: For RS-232 & RS-485

1, 3-pin pluggable header (male, Phoenix Contact MSTBA 2.5/3-G-5.08/AU or equivalent)


Serial Cable Connection: For RS-422

1, 5-pin pluggable header (male, Phoenix Contact MSTBA 2.5/5-G-5.08/AU or equivalent)


5.       How do I begin to use a 1782-JDCx gateway?

You can begin to use a 1782-JDCx gateway by following the User’s Manual Quick Start instructions.


6.       What are the LEDs on the 1782-JDCx indicating?

There are two sets of LEDs on the unit. The two green LEDs next to the serial connector are used as indicators for activity on the serial communication receive and transmit ports. The other two bi-color LEDs are used to indicate the DeviceNet module (MS) and network (NS) status. For troubleshooting or further information on status definitions corresponding to LED actions see LED Operation in the 1782-JDCx User’s Manual.


7.       On what DIN rail can I mount the 1782-JDCx?

The 1782-JDCx can be mounted on DIN rail mount EN50022 (WRC50022).


8.       What are some common applications for the 1782-JDCx gateway?

A 1782-JDCx gateway provides DeviceNet communications for weigh scales, bar code readers and scanners, display panels, robots, drives, operator stations / HMI, magnetic code readers and other ASCII serial devices.


9.       Are the 1782-JDCx gateways designed to plug-n-play?

Yes, the 1782-JDCx gateways are designed to plug-n-play using our factory default settings: serial framing of 7N2, serial baudrate of 9600, max number of receive and transmit characters set to 20, pad mode off, etc. The full list of default settings can be found under Default Settings in the User’s Manual.

If you wish to change any parameters from their default settings you will need to use a DeviceNet software configuration tool. Many of these tools have EDS readers, which make the editing process easier.


10.   Does a 1782-JDCx gateway provide electrical isolation?

Yes, a 1782-JDCx gateway provides 1000V network electrical isolation.


11.   What are the currently available 1782-JDC-x gateway models?

1782-JDC-1: Isolated RS232 Interface

1782-JDC-2: Isolated RS485 Interface

1782-JDC-4: Isolated RS485/RS422 Interface

1782-JDCE-1: Isolated RS232 Interface with Enhanced Parameters 


12.   On what DeviceNet baud rates does the 1782-JDCx communicate?

The unit works with 125k, 250k or 500k baud rates. It is default set to autobaud on DeviceNet. A fixed baud rate of 125k, 250k or 500k may also be assigned with a software configuration tool.


13.   On what baud rates does the serial port communicate?

The serial port on the 1782-JDCx will communicate on baud rates of: 1200, 2400, 4800, 9600, 19.2k, or 38.4k baud.


14.   How do I connect a 1782-JDCx gateway to a serial port device?

You connect the JDCx to a serial port device with the Phoenix connectors on the unit which are labeled for which signal goes in each port of the connector. For RS-232 or RS-485 communications the signal/pin assignments are as follows:


Pin #










Signal -




Signal +






For RS-422 communications the signal/pin assignments are as follows:


Pin #






Transmit -



Transmit +






Receive -



Receive +


15.   How is the Master Handshake mode different from the Hardware handshake RTS/CTS?

Master Handshake mode is a data control mechanism between the DeviceNet master and the 1782-JDCx (after the JDCx receives data from serial device), communicated in IO message. The 1782-JDCx indicates new data arrival and waits for Master to issue a new record number, to be used with new data. The hardware handshaking via RTS/CTS (which is not supported in the 1782-JDCx) requires two additional signal lines on the serial side and it controls the data before it is received.



16.   When should I turn Pad Mode ON? Or what configuration parameter should I check when the scanner cannot stay connected to the 1782-JDCx due to an IO size error?

If the DeviceNet scanner or the master device needs to be pre-configured with an input (produce) size before making a connection, or if the serial device will be sending variable data size strings, you will need to turn the PAD Mode ON. This parameter should be checked if the 1782-JDCx 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. In the Master Handshake mode, the program should be looking at the New Data bit in status and if detected, should supply the new record number and wait for the 1782-JDCx to produce data along with that record number.


18.   What does the 1782-JDCx require for power?

The 1782-JDCx receives all necessary power from the DeviceNet network cable. This should be between 11 and 25 Vdc.  It consumes about 2 watts of power maximum.


19.   Where should I use a 1782-JDCx gateway vs. a 1799wr-DASCII gateway?

The 1782-JDCx has a form factor designed for DIN rail mounting and the 1799wr-DASCII is designed for panel mounting.  The 1782-JDCx models are functionally very similar to the 1799wr-DASCII.  The additional parameters of the 1782-JDCE-1 are most similar to the 1799wr-DASCII and offer some additional flexibility.  Also the 1799wr-DASCII is designed for RS232/422/485 serial communication, whereas the 1782-JDCx models are designed for a specific serial communication type.



20.   How do I access the serial ASCII data from a 1782-JDCx gateway?

When configuring your PLC, you have the option to memory map the ASCII data from the 1782-JDCx to a location on your PC. The ASCII data can be found at this location.


21.   When do I need to use an EDS (electronic data sheet) file for a 1782-JDCx gateway?

An EDS file is not necessary, but it makes configuring the 1782-JDCx (changing baud rate, framing, etc.) far easier than if you were to try to change the device parameters by editing the attributes of certain class objects and instances without the aid of a configuration tool. There are many software configuration tools available with EDS readers that can be used to set up the device.


22.   What is the proper cable to use for a 1782-JDCx gateway serial connection?

The proper cable selection depends upon which gateway model is used, the serial communication baud rate desired and the total cable length.  Cable selection guidelines:


1782-JDC-1: RS232 3 wire shielded

1782-JDC-2: RS485 3 wire shielded

1782-JDC-4: RS485/RS422 3 wire (RS485) shielded or 5 wire (RS422) shielded

1782-JDCE-1: RS232 - 3 wire shielded


23.   Where can I purchase the proper cable for a 1782-JDCx gateway serial connection?

You can purchase the proper cable from many suppliers and fitted with the connectors required for the gateway model and serial device being used.