What the part is
The Omron CS1W-ID291 is a 96-point digital input module in the CS1W series, designed to mount on the CS backplane and land field wiring through a rectangular connector. Bulk-packaged and approved to CE, CSA, Lloyd, NK, and UL, it slots into the same CS chassis as the rest of the CS1W I/O family without special retention hardware.
Slot density and field-wiring practice
With 96 discrete inputs on a single module, the ID291 is the high-density pure-input option for CS1W panels - useful where a full rack of binary sensors needs to be absorbed without burning chassis slots on combo cards. Termination is via rectangular connector rather than plug-in terminal blocks, so wiring harness build-up goes in ahead of commissioning rather than field-stripped per point - layout the connector pin map against the sensor schedule before the panel is populated.
Cross-shopping against same-class CS1W siblings
The closest same-series peer is CS1W-MD292: a 48-in/48-out combo module on the same CS backplane with the same rectangular connector pattern - function for function it splits the 96-point ID291 into a mixed I/O card, useful only if half the new points are outputs. For lower-density 32-in/32-out roles the CS1W-MD262 keeps the same chassis and connector family, so a drop-in path exists within CS1W if a project is downsized rather than abandoned.