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Type
| Function block |
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Description
| The
FPID function block is a second order Proportion + Integral + Derivative loop controller. It is possible to choose either the remote (TRUE) or the local set point (FALSE) by setting the REMOTE input. The AUTO input declares if the FPID works automatically or is set manually.With the interlock feature a fixed value can be set as output value (e.g., in case of a controller error). Also a low (LOW) and a high value (HIGH) can be declared in order to set limits for the output value.The Manual>Auto and the direction switch only work without shocks if there is an integral part.
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State
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0 |
1 |
| Set point switch | Local | Remote direction switch |
| Auto switch | Manual | Auto |
| Interlock switch | Normal | Interlock |
The high and low ranges of SPR, SPL and X must be identical.The high and low ranges of Manual and X are 0 to 100%. |
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Notes
| Function blocks have to be instantiated. The instance name of the function block has to be declared in the 'Variables' table of the POU where the FB is going to be used. The instance name must be unique within the POU. |
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Parameters
|  REMOTE
| Data type: | BOOL |
| Description: | Switch between remote (TRUE) or local set point (FALSE). |
AUTO
| Data type: | BOOL |
| Description: | Switch between automatic (TRUE) or manual control (FALSE). |
DIRECTN
| Data type: | BOOL |
| Description: | Switch for setting direction of controlling (TRUE means inverted controlling). |
INTLCK
| Data type: | BOOL |
| Description: | Switch for setting a defined value as controller output. In case of a controller error this switch may be set to TRUE, then the INTLCKV will be set as controller output. |
Tscan
| Data type: | REAL |
| Description: | Duration time between function block calls (in sec). |
Yman
| Data type: | REAL |
| Description: | Manual value for manual control. |
SPR
| Data type: | REAL |
| Description: | Remote set point (1. set point). |
SPL
| Data type: | REAL |
| Description: | Local set point (2. set point). |
X
| Data type: | REAL |
| Description: | Regulating variable (actual value). |
KP
| Data type: | REAL |
| Description: | Proportional constant. |
TI
| Data type: | REAL |
| Description: | Reset time (in sec). |
TD
| Data type: | REAL |
| Description: | Derivative time constant (in sec). |
HIGH
| Data type: | REAL |
| Description: | Highest limit of controller output. |
LOW
| Data type: | REAL |
| Description: | Lowest limit of controller output. |
INTLCKV
| Data type: | REAL |
| Description: | Interlock value. |
Output
Yout
| Data type: | REAL |
| Description: | Regulating value (output value). |
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