Why doesn Indexer LPT support more motors per parallel port?
Parallel ports are inexpensive, rugged and readily available. Indexer LPT associates a set of inputs and outputs to a group that it calls an “axis”. Each “axis” includes outputs for “pulse”, “direction”, two limit switch inputs to sense extents of positive and negative motion, a general purpose input and two general purpose outputs. Two sets of these groups are designated on each parallel port connector. Every group (axis) is identical in function and handled similarly in software, thereby greatly simplifying application design, and avoiding the types of compromises that would otherwise be necessary. Outputs and inputs can be software configured for general and special purposes as well. Indexer LPT can control and monitor up to eight outputs and six inputs on each parallel port, and support as many as four parallel ports per system – though one of these ports, which is used for the Hardware Assist Module (that houses the feed rate override electronics), has four outputs and six inputs
