Easy Electronics xLogic Micro PLC - Page 195

195
Fulllevel1 Vatand/orreservoirfillingwithout
drain
1,0 1 +
Fulllevel2 Vatand/orreservoirfillingwith
drain
0,7 20 +
Characteristicswhenconfiguring
ObservetheControlandregulatebasics.
Controlandregulate
Inengineering,quantitiescanbebothcontrolledandregulated.
Whencontrolling,aquantityismanipulatedwithoutbeingabletocompensateforoutsideinfluences.
Whenregulating,aquantityismaintainedataspecificvalueinordertocompensateforoutside
influences.
Inthefollowingexample,controllingmeansthatthepersoncansettheheatoutputatafixedvalue.The
heatercannotcompensateforthedropinroomtemperaturewhenawindowisopened.
Intheexamplebelow,regulatingmeansthatthepersoncanincreasetheheatoutputiftheroom
temperaturedropstobelow20 °C.Iftheroomtemperaturerisesabove20 °C,theheatoutputis
reduced.
Basicconceptsofregulating
Intheexample,thecurrentfortheelectricheatingisthemanipulatedvariable.Thechangeable
resistanceistheactuator.Thehandthatoperatestheactuatoristhecontrol.Theactualroom
temperatureisthecontrolledvariableortheprocessvalue.Thedesiredroomtemperatureisthe
commandvariableorthesetpointvalue.Theelectricheatingisthecontrolprocess.Thethermometeris
thesensor.Thetemperaturelossfromopeningthewindowisthedisturbancevariable.
Sothismeansthatthepersonmeasurestheprocessvalue(roomtemperature)withthesensor