Citect MeasureX Driver

Honeywell-MeasureX is an industrial microprocessor based system for monitoring quality parameters related to continuous flat sheet paper production.

The Citect MeasureX driver communicates to the Honeywell-MeasureX MX-Open system via the Open Data Exchange (ODX) interface. The driver has been designed using the Front End / Back End driver model recommended by Citect. In this model the driver has two parts, the Back End and the Front End.

The Back End communicates with the MeasureX IO Device without receiving any requests from Citect. As Citect starts, the variable tag databases are read by the driver to provide a list of tags that will be needed by Citect. This list of tags is then sent to the MeasureX device as a periodical read request. The MeasureX will then send read responses to the requested data at specified intervals. The Back End of the driver will receive the data read responses and store the data in memory buffers.

The Front End of the MeasureX driver will process the commands from Citect. To process a request, the Front End will extract the data from the memory buffers and respond to Citect using that data. When a tag needs to be written, the Front End will pass the write commands to the Back End to be serviced. Figure a provides a general overview of the process.