The DVN Driver license is a permanent, commercial license, which must be purchased. This license is automatically activated during driver installation.

A time-limited-license version of this driver is available upon request.

The driver must be started before any applications attempt to connect to it, specifically before the DR_ApInitIPC function is called by a client. The driver requires the Cascade NameServer (nserve) and Cascade QueueServer (qserve) to be running, and will automatically start them if they are not. The driver may be started before or after the Cascade DataHub is started.

The DVN Driver makes privileged calls to map the shared memory of the card, and thus must be run with root privileges. The installation makes the DVN Driver set the user ID (using setuid) to root by default. The DVN Driver can be started at a shell using the command drsstdvn and specifying any of its command options. For example:

# drsstdvn -f ./c2.cfg

or, with more options:

# drsstdvn -d dh3 -f ./c2.cfg -n SST-DNDriver02

To test the DVN Driver, you can run it in auto-detection mode using the following command:

# /usr/cogent/bin/drsstdvn -f /usr/cogent/src/drsstdvn/detect.cfg

This command will attempt to start the DVN Driver, will auto-detect up to 4 installed SST DeviceNet cards, and then run in time-limited mode if no license is installed.

You can now create your own driver configuration file to reflect your particular setup (see Driver Configuration for details). The DVN Driver ships with a number of sample files that are copied to /usr/cogent/src/drsstdvn/ by the installation script. For example, you can run the driver with:

# drsstdvn -f sstdvn_sample.cfg

If there are errors in the configuration file, the driver will exit with messages indicating the nature of the errors.

Once the DVN Driver has started, it will begin a periodic poll of the I/O hardware. This information is stored within the driver, but is not actually transmitted anywhere until you have created a client application. If you prefer, you can download the Cascade DataHub development archive from the Cogent web site. This datahub acts as a universal client and server for process data. You can examine and modify the contents of the Cascade DataHub using one of the commands: readpt, writept, waiter and dhview.

In order to use the Cascade DataHub with the DVN Driver, the driver must be configured to use the point interface through the configuration commands: digital, analog and group in the .cfg file.

To use the Cascade DataHub see Using the Cascade DataHub in the Cascade DataHub manual. To examine and modify the contents of the Cascade DataHub, see Using the Cascade DataHub Viewer.