IS220PAICH1A is an Analog I/O Pack developed under Mark VI series GE. Simplex and Triple Modular Redundant (TMR) Mark VI control systems are available for small applications and big integrated systems with control ranging from a single module to many distributed modules. The system's throughput allows for the operation of up to nine 21-slot VME racks of I/O boards in 40 milliseconds, including data voting. In a method known as Software Implemented Fault Tolerance, inputs are voted in software (SIFT). Each control module's VCMI board gets inputs from the control module backplane and other modules via its own IONet.
In addition to general-purpose I/O, the Mark VI has a number of boards that are specifically designed for direct communication with specific sensors and actuators. In many situations, this minimizes or removes a significant amount of interposing instrumentation. As a result, numerous possible single-point failures in the most crucial area are removed, resulting in increased operational reliability and lower long-term maintenance costs. The diagnostics can also directly interrogate the devices on the equipment for optimal effectiveness thanks to the direct connectivity to the sensors and actuators. This information is used to evaluate the performance of devices and systems. The elimination of peripheral instrumentation reduces spare parts inventories, which is a subtle benefit of this design.