Overview:

Ethernet device servers offer the ability to quickly connect a serial device, such as a MicroSMART PLC, into a new or existing network.

In the past, connecting a serial device to a computer in a Control System required special wiring and converters.  EIA-232 serial communications typically reduced the distance between devices to 50 feet.  While Ethernet systems using switches or hubs and CAT-5 wiring allow you to easily place equipment anywhere on the network with supported distances of well over 100 feet, as well as support for multiple devices.

However, Ethernet enabling only solves half of the communication problem.  To fulfill the application requirements one must use an OPC or DDE software server, such as IDECs WindSRV, which uses Ethernet encapsulation.  Ethernet encapsulation is a special software routine built into the software to transport the serial information over the Ethernet network.

The following sample is for Point-to-Point communications:

  System Requirements:

  Typical System Layout:   

Setting up the Digi One IA (RealPort):

1. Connect the Digi One IA (RealPort) Device Server to the PS5R power supply and the power supply to a 120VAC outlet.
2. Connect the Digi One IA (RealPort) Device Server's Ethernet port to the network.
   NOTE: This should be on the same subnet as the Windows PC you will be using to configure the device.
3. Load the Digi Port Authority - Remote application from the Access Resource CD you received with the product (or download from support.digi.com) onto the Windows PC.
4. Start the Digi Port Authority - Remote application by going to Start>Programs>Digi>Digi Port Authority Remote.  
5. Make sure ADDP is selected as the Discovery Protocol.
6. Click Discover.  This will locate all Digi Device Servers on the local network.  Next, you will get one of the following:
1. If the local network uses DHCP:  The Digi One IA (RealPort) Device Server will get an IP Address from the DHCP Server.  If a Static IP Address is desired, select the Digi One IA (RealPort) Device Server's IP Address and click Configure.  Login to the Digi when prompted for a login, disable DHCP and assign a static IP Address to the Digi One IA (RealPort) Device Server.
   
2. If the local network does NOT use DHCP: The Digi One IA (RealPort) Device Server will have an IP Address of 0.0.0.0.  A message window will pop up asking you to select the device and click Configure to set the IP Address for the Digi One IA (RealPort) Device Server.
   
7. Reboot the Digi One IA (RealPort) Device Server.

Configuring the Digi One IA (RealPort) Serial Port:  

1. Open a browser window, point to the IP address of the Digi One IA (RealPort) Device Server, and login as root (or use Digi Port Authority Remote as shown above).
   
2.  A screen like this should appear:  
   

3. Choose Configure from the list on the left side of the screen. Then choose Port from the expanded menu list.
   
4. In the Device Type drop down box, change the device type for port to Printer.
   
5. Configure the following:
   a. Terminal type:   You can leave as is.  It is not applicable for device type Printer.
   b. Flow control:    Software
   c. Baud rate:         9600
   d. Data bits:          7
   e. Stop bits:          1
   f. Parity:               Even
   
   
6. Always check the port settings for each PLC before proceeding.  These settings much match between the PLC’s serial port and the Digi One IA (RealPort) Device Server.  After ensuring the port settings match, click Submit to save the configuration to the Digi One IA (RealPort) Device Server. 
   
7. Depending on the Digi model, there may be four DIP-switches to set on the DIGI Device Server's serial port.  This can be set to EIA-232/422/485.  
   NOTE: For IDEC PLCs set the DIP-switches for EIA-232 configuration, which is switch 1 “ON” and all remaining switches
   “OFF”.
   
8. The DIGI One IA (RealPort) Device Server is successfully configured for communicating between the PLC and the Windows PC.

PLC setup is not required, because the WindSVR software is designed to communicate with the PLC in its standard programming format. The addition of or use of a second port to the PLC is strongly recommended.  Use the second port with its default settings and IDEC’s Maintenance Protocol.  This can be found in the WindLDR software under “Configure”, “Function Area Settings” and “Communication”. 

Setting up the WindSVR (KEPServerEx):

NOTE:  These instructions are in addition to the instructions given with the Digi One IA (RealPort) Device Server. Please, always refer to the manufacturers instructions first for setting up your equipment and making cable connections.  

The procedures for setting the WindSVR Software parameters are fully covered by the simple instructions included in its help screens.   As a suggestion, please spend some time with the OPC server software.  Use the serial communications mode, to communicate, to a demo PLC.  Develop your skills at using this amazing tool.

1.    Open the OPC server software by clicking on the desktop icon.  The screen should look something like the following screen shot:
      

2.    Right click on Channel1 and select Properties.  

3.    Set up the Channel Properties as follows:
       a. Select the Tab box, General.
       b. Give the channel a name, in this case use Channel1,
       c. Then select a Device driver; in this case it would be the IDEC driver.
          

4.    Under the Communications Tab check the Use Ethernet encapsulation box.  This means the serial communication packet will be
       encapsulated in an envelope created by the WindSVR software and sent over the Ethernet.  
       NOTE: Notice the serial port setup is no longer available.
      

5.    Make sure the remaining tabs are configured to meet your requirements.  
       NOTE: In most cases you will be using the default settings or no functions from those boxes.

6.    Select OK to return to the main screen.

7.    Set the Device parameters by right-clicking on Device1.
      

8.    Select Properties.
        
9.    Under the General Tab set the following:
       a. Name: A description or name for the PLC device.
       b. Model: The type or brand of PLC.
       c. ID: is the network, numeric ID of the PLC (in Point-to-Point applications it usually defaults to “0”)
       d. Decimal: The format by which data is transferred from the PLC to the Windows PC.
       e. Data collection: Check the Enable Data Collection box.
         

10.    Under the Ethernet Encapsulation Tab set the following:
         a. IP Address: The IP Address of the Digi One IA Device Server.
         b. Port Number: The TCP port that designates the serial port on the device server. 
             NOTE: The Digi One IA Device Server uses 2101 to identify the serial port for a raw connection.
         c. Protocol: The Ethernet communication protocol.  In this case it is TCP/IP, which is also the most common protocol.
            

11.   Select OK when finished to return to the main KEPServerEx screen.

12.   To start the communications locate the button on the tool bar with the Hammer and letters OPC on it.  Click the button to start the
        Kepware Quick Client Software and establish the OPC connection through the Ethernet system to the PLC. 

A good indication that communications is was successful is if most of the LEDs on the Digi One IA (RealPort) Device Server are lit or flashing and green. If you see a red LED then you may have a communication problem, most likely no link to the Ethernet network.  Try to ping the Digi from the Windows PC.  You can also use the Digi Port Authority - Remote application to help troubleshoot any problems. 

If you need further assistance please feel free to call IDEC technical support at 1-800-262-4332