When designing a PLC control panel, one of the fundamental decisions is how to provide overcurrent protection for I/O modules. Should each I/O module be fused with a single fuse, or should each I/O point be fused individually? Here are 11 things to consider when deciding how and when to fuse I/O points.
1. Always follow specific customer project requirements and specifications when they are provided. Note that many times it is appropriate from an electrical standpoint to fuse each I/O module with a single fuse. However, customers may require individual fusing per I/O point (or per field device) so that one fault only disrupts the one point.