User Guide - Eurotherm Ltda

nanodac RECORDER/CONTROLLER: USER GUIDE4.5 VIRTUAL CHANNEL CONFIGURATIONThis allows the configuration of maths channels, totalisers and counters. The configuration is divided intothe following areas: ‘Main’, ‘Trend’, ‘Alarm 1*’ and ‘Alarm 2*’. Items appearing in the ‘Trend’, Alarm 1’ and‘Alarm 2’ areas are identical with the equivalent items described in Section 4.4 (Input channels), above.*Note: Virtual channels 16 to 30 (supplied with Modbus Master and EtherNet/IP options only) comewithout alarms.4.5.1 Maths channel configurationThe following maths functions are available (listed in up-arrow scroll order)Off, Add, Subtract, Multiply, Divide, Group Average, Group minimum, Group maximum, Modbus input,Copy, Group minimum (latch), Group maximum (latch), Channel maximum, Channel minimum, Channel Average,Configuration revision, Off.Figure 4.5.1 shows a typical maths channel configurationVirtual Channel.1.MainDescriptorTypeOperationPVStatusResolutionUnitsInput1Input2VirtualChan1MathAdd180.36 UnitsGood2Units93.49°C86.8°CFigure 4.5.1 Maths channel configuration (typical)DescriptorTypeOperationPVStatusResolutionUnitsInput1Input 2ResetTime RemainingPeriodAllows the user to enter a descriptor (20 characters max.) for the maths channelMath selected for this example. (See Section 4.5.2 and Section 4.5.4 for totalisers andcounters respectively.)Allows the user to select the required maths function. See ‘Maths Functions’, below.Read only. Shows the dynamic value of this channel in the units entered in ‘Units’ below.Read only. Shows the status of this channel, reflecting the status of the input sources.Enter the number of decimal places requiredAllows a five character string to be entered to be used as the channel units.The value of input 1. May be entered manually, or it may be wired from another parameter(Section 7). Uses the resolution of the source.As for ‘Input 1’, Appears only when the operation requires two inputs.Allows the user to reset latching functions (e.g. Channel Max) or averaging functions(e.g. Channel Avg). Reset is carried out by setting the field to ‘Yes’, then operating thescroll key. The display returns to ‘No’. Alternatively the function can be reset by anotherparameter wired to ‘Reset’.The period of time remaining before the virtual channel performs its operation. For example,the time remaining for the maths channel average operation to sample the inputbefore performing the calculation.For averaging functions, this allows a period to be entered, over which the value is tobe averaged. Selectable periods are: 0.125, 0.25, 0.5, 1, 2, 5, 10, 20, 30 seconds, 1, 2,5, 10, 20, 30 minutes, 1, 2, 6, 12, 24 hoursHA030554Issue 7 Nov 12Page 89