Chris Dobson (Ainsworth Technologies, Canada)
The project's goal was to create a multi-axis machine controller for tube bending equipment. The control included a real-time control component, and a user interface. To accomplish this, two computers were used. One running QNX 4.2 for the real-time control, the other running NT 4.0 Workstation for the user interface and external connections.
We use Cogent's Cascade Connect for the NT/QNX communications. It saved us considerable time during development. It also removed one source of potential problems. The performance is good and the product is relatively easy to use. It is certainly a much better solution that developing the connection software from scratch.
In the control, each physical subsystem is controlled by a QNX task. Functionality such as administration, sequencing, interference, and safety is provided by other QNX tasks. To accomplish communications between the tasks, Cogent's Cascade DataHub, was used. The data base supplied a central point for task communications. Tasks can easily send and receive messages via the database without having to make major changes. The real benefits are the following.
The communications between tasks can be monitored using the DataHub.
Often adding a new task that is co-ordinated with other tasks, will not require the changing of the other tasks. This is possible since the new task can be triggered from existing database points.
The DataHub allows the development and testing of co-ordinated tasks without all the tasks being written. The communication is simulated by setting and reading database points.
The digital IO control component uses Cogent's driver for the Hilscher Interbus card. This combination was selected due to high speed IO requirements and easy integration to the Cascade DataHub. Using the data base for the IO allows any task to monitor the status of the physical equipment.
For most of the people on our team, this was their first QNX project. One of our team members was supplied by Cogent. He became an integral part of the team, providing the expertise we needed for QNX. Questions/issues with the Cogent products were directed through him back to the Cogent technical group for resolution.