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173

Accessing I/O Data Via TruePort

Introduction

Analog and Digital I/O data, as well as output control, can be accessed in several ways. To have

access from an application running on a workstation or server, the I/O Applications Program Interface

(API) provided within Trueport can be used. This API uses a command/response format to get or set

data on each individual I/O channel register. A sample program (

ioapiotp.c) demonstrating typical

usage can be found on the IOLAN product CD-ROM.

Setup

After TruePort has been properly installed and configured on the workstation or server and initiated

from the application, it will setup a connection to the appropriate IOLAN. It will then be available to

relay commands to the IOLAN and communicate responses back the application. TruePort will create

a COM port to which the application can write commands to and read responses from. Since all

communications are done via this COM port, the application need only use standard serial

communication interface calls.

The following steps should be taken:

1. Install the Trueport software on the server or workstation on which the application will be

running.

2. Configure the virtual communication port (COM) (see TruePort User Guide for details)

3. Run the application. Typically the application will:

1. Open the COM port.

2. Send Commands to the COM port using standard write commands.

3. Read Responses from the COM port using standard read commands.

Note:

All commands are forwarded to the IOLAN over the network where the specific I/O

channel registers are modified or read, and then responses are sent back to TruePort

where they will be made available to be read from the COM port.

4. Once the desired operations are completed, the COM port can be closed.

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Perle Systems Switch DS1 Manual do Utilizador Página 173