Control systems must be protected against fluctuations and power loss, whether electrical or fluidic. Fluctuations and losses are well defined in IEC, IEEE and ISO standards. Careful design of electrical systems, including the use of UPSs for electrical control systems and the careful design of pneumatic supply systems, including the proper sizing of pneumatic accumulators for compressed air-powered logic, is essential.
The local control function is important to understand when designing machinery control systems. If the failure of the local control function could lead to increased risk to the user, it is a safety function. This article explains the local control function from a functional safety perspective.Read More