The following SIL3 digital input application wiring examples are described, below:
Cat2/PLd:
a single sensor wired to one input.
Cat2/PLd with high availability:
two sensors wired to two input points on different input modules.
Cat4/PLe:
two sensors, each wired to a different input point on the same input module.
Cat4/PLe with high availability:
two pair of sensors (for a total of four sensors): the sensors of the first pair are each wired to a different input point on one module, and the sensors of the second pair are each wired to a different input point on a second module.