Setting up Passthrough Connections 111

Setting up a passthrough connection involves a number of steps.

‰ Using SMP Config, you identify the devices that will be accessed through passthrough connections. For each device, you provide information such as the SMP Gateway port to be used for the passthrough connection, and the timeout after which the passthrough connection is to be terminated after the last data exchange.

‰ In SMP Connect, you identify each application that will communicate with a device via a passthrough connection. For each of these applications, you specify the type of loopback connection to be established between SMP Connect and the application, and you define the communications settings of the loopback connection.

14.2.1

Defining SMP Gateway Passthrough Settings

Using SMP Config, define the SMP Gateway passthrough settings for each device that will be using a passthrough connection:

‰ In the left pane, click Passthru Connections.

‰ Create a new connection by entering the following information in the empty row:

‰ IED Name.

This name will be used to identify the device in the SMP Connect program. You should use the same name that you assigned to the device when configuring the master protocol component that it communicates with.

SMP Gateway and specify here the port that will be used by the IED maintenance and/or configuration programs; otherwise, the port must be the same as the one used by the master protocol.

‰ Suspend Link.

This setting indicates that data acquisition should be suspended for all other devices sharing the multidrop link while SMP Connect is communicating with the selected device. If selected, acquisition of the remaining devices will be suspended. This setting applies only to devices that support the feature.

‰ Suspend IED.

This device-specific setting indicates whether or not the master protocol component should suspend data acquisition while SMP Connect is communicating with the device.

‰ IED Address.

This address identifies the device in a multidrop configuration. This setting is ignored if the Suspend IED checkbox is not selected.

‰ Modem Signals.

This setting specifies whether or not the serial port associated with the IED supports modem control signals. If selected, the DTR and RTS modem control signals will be transferred across the passthrough connection. By default, modem control signals are NOT transferred.

‰ Locked at Startup.

This setting is a security feature. If selected, the passthrough connection will not be available when the SMP Gateway starts up. You can subsequently make it available by enabling specific logical data points, as explained under “Locking Incoming RAS and Passthrough Connections”, page 106.

‰ Inactivity Timeout.

This mandatory setting specifies how long the passthrough connection link established by

SMP Connect can remain inactive. If the program detects that no data exchange occurred

between the device and the application during the specified timeout period, it prompts the user to either terminate the session or specify a longer wait time.

‰ Comments.

This optional setting is used to store the instructions that will be displayed to the SMP

Connect operator, such as telling him which communications program to use with the

device.

14.2.2

Installing a Loopback Cable, if Necessary

There are 3 types of loopback connections that you can set up between the device manufacturer’s maintenance or configuration application and SMP Connect:

‰ A virtual serial loopback connection. This is the preferred choice.

‰ A real serial loopback connection.

You set up this type of connection only if the device manufacturer’s application cannot use a virtual communications port.

‰ A TCP/IP loopback connection.

You set up this type of connection only if the device manufacturer’s application uses TCP/IP.

TCP/IP and virtual serial loopbacks do not require any further physical modifications to the configuration.

To set up a real serial loopback connection:

‰ Configure the device manufacturer’s application to use one of the PC’s serial ports, COM1 for example.

‰ Attach a null modem cable to this serial port.

Note: A null modem cable is an RS-232 cable that crosses the sending wire with the

receiving wire.

‰ Instead of attaching the other end of the cable, to the device, attach it to a second serial port of the same PC, for example COM2.

Note: Most modern PCs are equipped only with a single serial port. If virtual

communications ports are not supported by the application and the PC is only equipped with a single serial port, a serial expansion card must be installed on the PC.

14.2.3

Setting Up a List of Applications and Loopback

Connections

SMP Connect communicates with the device manufacturer’s application via a loopback

connection. There may be several applications running on the PC. You have to identify all the available applications, and for each application that must remotely access a substation device, you have to provide the following information:

‰ Specify whether the application is to be started manually, identify the path to the application, and provide any arguments required by the program.

‰ Specify what type of loopback connection is to be used between SMP Connect and the application, and define the communications settings of the loopback connection. Loopback connection types are described in section 14.2.2, above.

To start SMP Connect:

‰ Select your SMP Gateway in SMP Manager’s application window.

‰ In the Tools menu, select SMP Connect.

The top portion of the screen shows the settings you entered in SMP Config, with one additional piece of information: the PThru Active column, which indicates whether a passthrough

connection is currently being used for a particular device. The bottom portion of the screen shows a trace of passthrough connection events.

To identify the application program that will communicate with a device, and to define the communications settings of the loopback connection used for that matter, proceed as follows:

‰ Select the device in the top pane of the SMP Connect window.

‰ In the Control menu, select IED Application Settings. The IED Application Settings dialog box appears.

To add an application to the list:

‰ In the IED Application Settings dialog box, click Add.

‰ In the dialog box that appears, type the application’s name and click OK.

‰ Under Application Settings:

‰ Specify whether the application is to be started manually. If you select to start it

manually, then when you connect to the device, SMP Connect will start the passthrough and loopback connections without starting the application; you will be able to start the application manually.

‰ Type the complete path to the application’s executable file.

‰ Type the command line arguments required by the application, if any (see the manufacturer’s documentation).

‰ Under Local Communication Settings:

‰ Specify whether SMP Connect is to use a virtual serial loopback, a real serial loopback, or a TCP/IP loopback connection to communicate with the NVT. Most manufacturers’ tools use a serial (virtual or real) connection. However, if you are using a terminal emulator program such as Microsoft HyperTerminal to communicate with the device, you can use a TCP/IP loopback connection.

‰ Click Configure to specify the loopback connection’s settings:

‰ The application port (serial only).

‰ The communications settings, such as parity, data bits, stop bits, flow control (serial only).

‰ The SMP Connect port (real serial only).

‰ The logical port number for the TCP/IP connection; type the same TCP/IP port number that you set in the device manufacturer’s tool or in the HyperTeminal program (TCP/IP only).

‰ An indication whether your application uses the Telnet protocol, or not. Most terminal applications using TCP/IP do use the Telnet protocol, so the checkbox is selected by default (TCP/IP only).

‰ Under Remote Communication Settings:

‰ Specify whether you want the passthrough server to wait until the application’s first data transmission before initializing the connection between the device and the SMP Gateway, or initialize it as soon as the application is started.

‰ Specify whether you want the passthrough server to automatically reset the passthrough connection upon transmission failure. If you select this checkbox, specify the time to wait following the detection of the transmission failure before resetting the connection.

Note: You can also use the Apply base settings for arrow-button to apply default base

settings for some type of applications.

Repeat the previous steps for all applications. Make sure you click OK to save the settings and close the IED Application Settings dialog box.