User Guide - Eurotherm Ltda

nanodac RECORDER/CONTROLLER: USER GUIDE4.6.4 PID menu parametersNote: If control type is set to ‘Off’, or ‘OnOff’ in the Setup menu, the PID menu contains only theLoop Break time parameter ‘LBT’.Sched Type Selects the type of gain scheduling (section B2.3.7) to be applied.Off. Gain scheduling not activeSet. The user selects the PID parameter set to be used.Setpoint. Transfer from one set to the next depends on the setpoint valuePV. The transfer from one set to another depends on the PV valueError. The transfer between sets depends on the value of the error signalOP. Transfer depends on the value of the output.Rem. Transfer is controlled by a remote input.Number of Sets Allows the number of sets of PID parameters for use in Gain scheduling to be selected.Remote input For ‘Sched Type’ = ‘Rem’ only, this shows the current value of the remote input channelbeing used to select which set is active. If the remote input value ≤ the Boundary 1-2value (see below) then set 1 is selected. If it is > Boundary 1-2 value but ≤ Boundary 2-3 value then set 2 is used. If the remote value is > Boundary 2-3 value, then set three isused. If the Remote input is not ‘wired’, the value is user editable from the front panel.Active Set The set number currently in use.Boundary 1-2 For all Sched Types except ‘Set’, this allows the user to enter a ‘boundary’ value, whichmeans that if the relevant value (SP, PV, Error etc.) rises above this boundary, the loopswitches from PID set 1 to PID set 2. If it falls below the boundary value, the loop switchesfrom set 2 to set 1.Boundary 2-3 As above but for switching between sets 2 and 3.PB/PB2/PB3 Proportional band for set one/two/three. The proportional term in the units (Engineeringunits or %) set in ‘PBUnits’ in the Setup menu. See Appendix B section B2.2.2 formore details.Ti/Ti2/Ti3Integral time constant for set one/two/three. Valid entries are1 to 9999.9 seconds, or‘Off’. If set Off, then integral action is disabled. Removes steady state control offsets bymoving the output up or down at a rate proportional to the error signal.Td/Td2/Td3 Derivative time constant for set one/two/three. Valid entries are 1 to 9999.9 seconds,or ‘Off’. If set Off, then derivative action is disabled. Determines how strongly the controllerreacts to a change in the PV. Used to control overshoot and undershoot and torestore the PV rapidly if there is a sudden change in demand.R2G/R2G2/R2G3 Relative cool gain for set one/two/three. Appears only if cooling has been configured(Ch2 Control not ‘Off’ or ‘OnOff’ in Setup menu). Valid entries are 0.1 to 10. Sets thecooling proportional band which compensates for differences between heating andcooling power gains.CBH/CBH2/CBH3 Cutback high for set one/two/three. Valid entries ‘Auto’ (3×PB) or 0.1 to 9999.9. Thenumber of display units above setpoint at which the controller output is forced to 0% or-100% (OP min), in order to modify undershoot on cool down. See section B2.3.2 formore details.CBL/CBL2/CBL3 Cutback low for set one/two/three. Valid entries ‘Auto’ (3×PB) or 0.1 to 9999.9. Thenumber of display units below setpoint at which the controller output is forced to 100%(OP max), in order to modify overshoot on heat up. See section B2.3.2 for more details.MR/MR2/MR3 Manual reset for set one/two/three. Valid entries 0 to 100%. Introduces a fixed additionalpower level to the output in order to eliminate steady state error from proportionalonly control. Applied instead of the integral component when Ti is set to ‘Off’.LBT/LBT2/LBT3 Loop break time for set one/two/three. valid entries are 1 to 99999 seconds, or ‘Off’.See section B2.3.6 for more details.Output Low/2/3 Output low limit for set one/two/three. Valid entries are in the range Output High/2/3to -100.Output High/2/3 Output high limit for set one/two/three. Valid entries are in the range Output Low/2/3to +100HA030554Issue 7 Nov 12Page 101