FB_PressureControlParams_PID
This function block contains a parameter set to be used by a FB_PressureControl_PID function block.
Syntax:
FUNCTION_BLOCK FB_PressureControlParams_PID IMPLEMENTS I_PressureControlParams_PID
END_VAR
VAR_OUTPUT
END_VAR
Properties
Name | Type | Access | Properties |
|---|---|---|---|
ChangeRate | LREAL | Get, Set | The ramp rate to use. |
Enable | BOOL | Get, Set | This property is used to activate and deactivate the proportional component of the PID controller. For details see Kp. |
EnableChangeRate | BOOL | Get, Set | A setpoint ramp function can be activated and deactivated. The internally used setpoint for the controller may be updated to the given setpoint by a limited rate, given as ChangeRate. This parameter is given in pressure units per second. A setting of ChangeRate:=0.0 or EnableChangeRate:=FALSE disables the ramp function and causes the internal setpoint to immediately follow the specified setpoint. |
EnableClipping | BOOL | Get, Set | A limiting function for the output can be activated and deactivated. For details see OutputLimit. |
EnableD | BOOL | Get, Set | The differential component of the PID controller can be activated and deactivated. For details see Td. |
EnableFeedForward | BOOL | Get, Set | A velocity pre-control can be activated and deactivated. For details see FeedForward. |
EnableI | BOOL | Get, Set | This property is used to enable and disable the integrating component of the PID controller. For details see Tn below. |
EnableM | BOOL | Get, Set | This property is used to enable and disable a negative output of the controller. |
EnableP | BOOL | Get, Set | This property is used to enable or disable a positive output of the controller. |
FeedForward | LREAL | Get, Set | A velocity feed forward component. When EnableFeedForward is set to TRUE, the value of FeedForward is multiplied by FeedForwardFactor and added to the PID response output. An active back pressure controller is used to match the injector backward velocity to the effect of the dosing axis. This function can be used to achieve a more dynamic adjustment to changes in turn rate. |
FeedForwardFactor | LREAL | Get, Set | This property is a parameter of the velocity feed forward function. For details see FeedForward. |
Kp | LREAL | Get, Set | The proportional gain of the PID controller. Enable must be TRUE to allow the calculation. The unit is velocity unit per pressure unit. |
OutputLimit | LREAL | Get, Set | A limit for the response of the controller. |
Reversed | BOOL | Get, Set | This property is used to invert the output of the PID controller. In a number of applications, the axis must move in the positive direction to relieve excess pressure. Typical examples are holding pressure and back pressure controllers in injection molding machines. |
Td | LREAL | Get, Set | The differential component of the PID controller. The response is calculated if EnableD is TRUE and Td and Tdd are >=cycle time, otherwise it is zero. The unit is velocity units * second per pressure unit. |
Tdd | LREAL | Get, Set | A parameter of the differential component of the PID controller. For details see Td above. |
Tn | LREAL | Get, Set | The integrating component of the PID controller. The response is calculated if EnableI is TRUE and Tn >= cycle time, otherwise it is zero. The output is limited to WuLimit. The unit is velocity units per (pressure unit * second). |
WuLimit | LREAL | Get, Set | A parameter of the integrating component of the PID controller. For details see Tn above. |
Methods
Name | Description |
|---|---|
This method is used to read BOOL parameters of the controller. For details see E_PressureControlParam. | |
This method is used to read LREAL parameters of the controller. For details see E_PressureControlParam. | |
This method is used to define BOOL parameters of the controller. For details see E_PressureControlParam. | |
This method is used to define LREAL parameters of the controller. For details see E_PressureControlParam. |