The 1791DS and 1791ES CompactBlock Guard I/O modules can provide the advantages of distributed I/O for different types of safety systems. The block I/O consists of small and self-contained remote I/O devices which includce not only a power supply, but also a programmable controller interface, input/output connections and a signal conditioning circuitry. The blocks are compatible with many allen bradley lines including the following: PLC-2, PLC-3, PLC-5/250 and PLC-5 family programmable controllers, and the SLC 5/02 modular controllers. Block I/O comes complete with I/O interface that include the functionality of the I/O rack, adapter, power supply, and I/O modules in one unit. To connect the unit simply connect sensors and actuators to the module and use the remote I/O cable to connect the block I/O to your programmable controller.