PLC-API Behaviour of the output: Description of the function: Internally, the controller uses a PWM function block that is used to control the thermal actuator. The mark-to- space ratio of the PWM function block is adaptively adjusted to the behavior of the controlled system. The PWM output is switched on as soon as the system deviation, fE, which is the setpoint minus the actual value, is greater than zero, and is switched off when the system deviation is less than zero. The mark-to-space ratio is not changed as long as the system deviation remains within the range [ -fOkRange ... fOkRange]. If fE > fOkRange, the mark-to-space ratio is increased by fStepSize.
After such an increase, time tWaitTime must elapse before the mark-to-space ratio can be changed again. If fE falls below -fOkRange, the mark-to-space ratio is reduced by fStepSize. The mark-to-space ratio is only modified over the range [fMinLimit ... fMaxLimit]. The period of the PWM signal is specified by the parameter tPWMPeriod. VAR_INPUT VAR_INPUT fSetpointValue : FLOAT; fActualValue : FLOAT; fManSyncValue : FLOAT; bSync : BOOL; eMode : E_CTRL_MODE; END_VAR fSetpointValue : Set value of the controlled variable. fActualValue : Actual value of the controlled variable. fManSyncValue :
Input to which the controller's mark-to-space ratio can be set, or with which the output can be set in Manual Mode. The output is set in Manual Mode if fManSyncValue > 0.0. TS4100 41 Version: 1.1