5. Programming on the device5.3 Circuit diagram elements5.3 Circuit diagram elementsA circuit diagram is a series of commands that the easyE4 device processes cyclicallyin RUN operating mode.Coils and contacts are interconnected in the circuit diagram. In RUN mode, a coil isswitched on or off depending on the power flow and coil function set.5.3.1 Function blocksFunction blocks are program elements with special functions. Examples: Timing relays,time switch, data block comparators. Function blocks are provided with or without con-tacts and coils. How a safety or standard function block is added to the safety or stand-ard circuit diagram and parameterized is described in→ Section "Working with function blocks", page 154In RUN mode the function blocks are processed according to the circuit diagram andthe results are updated accordingly.Examples:Timing relay = Function block with contacts and coilsTime switch = Function block with contacts5.3.2 RelaysRelays are switching devices that are emulated in easyE4 device electronically, whichactivate their contacts according to the assigned function. A relay consists of at leastone coil and contact.124 easyE4 11/18 MN050009 EN www.eaton.com
