Parallel Polling Overview
Although parallel polling is not widely used, it is a useful method for obtaining the status of more than one device at the same time. The advantage of parallel polling is that a single parallel poll can easily check up to eight individual devices at once. In comparison, eight separate serial polls would be required to check eight devices for their serial poll response bytes. The value of the individual status bit (ist) determines the parallel poll response.
You can implement parallel polling with either the traditional or multi-device NI-488.2 calls. If you use multi-device NI-488.2 calls to execute parallel polls, you do not need extensive knowledge of the parallel polling messages. However, you should use the traditional NI-488.2 calls for parallel polling when the GPIB interface is not the Controller, and the interface must configure itself for a parallel poll and set its own individual status bit (ist).
Related Topics:
Parallel Polling with Multi-Device NI-488.2 Calls