# ValveAnalog
## `ValveAnalog` (FB)
FUNCTION\_BLOCK ValveAnalog
### Short description
> Control of a continuous valve actuator with anti-blocking function and continuous position feedback\
> \
> Typical application: control valve in a heating circuit
### Representation
### Interfaces
#### Inputs
| Name | Data type | Value range | Initial value | Function |
| ---------- | ----------------- | --------------------------------------------- | ---------------------- | ---------------------------------------------------- |
| *rY* | REAL | | | Control signal from controller |
| *xForce* | BOOL | | FALSE | Forced override after manual override |
| *xAlarmIn* | BOOL | | FALSE | Actuator fault message |
| *rU* | REAL | | 0.0 | Position feedback from the control valve |
| *eAO* | HVACTYPES.eManNum | HVACTYPES.eManNum.Auto, HVACTYPES.eManNum.Man | HVACTYPES.eManNum.Auto | Feedback - automatic operation |
| *rPoti* | REAL | | | Feedback - control signal from hardware manual level |
#### Outputs
| Name | Data type | Value range | Initial value | Function |
| ------------- | --------------- | ----------- | ------------- | ----------------------------------------------- |
| *rHA* | REAL | | | Control signal after manual override |
| *rAA* | REAL | | | Control signal before manual override |
| *xAlarmPos* | BOOL | | | Fault message from position monitoring |
| *dtAbsLastOn* | DATE\_AND\_TIME | | | Date / time of the last anti-blocking operation |
| *xAlarm* | BOOL | | | Collective fault indication |
| *xAuto* | BOOL | | | Collective automatic-mode message |
#### Setpoints / parameters
| Name | Data type | Value range | Initial value | Function |
| ------------------ | --------- | ------------------------------------------- | ------------- | --------------------------------------------------------- |
| **udiControlTime** | UDINT | 0 … 600s | 180s | Duration of the position monitoring |
| **rControlDiff** | REAL | | 7.0% | Monitoring of valve position: maximum position deviation |
| **xControl** | BOOL | | TRUE | Enablement of the position monitoring |
| **xForceOption** | BOOL | | TRUE | State of the output *rHA* during forced override |
| **rAbsMaxLimit** | REAL | | 100.0 | Upper limit for the control signal before manual override |
| **rAbsMinLimit** | REAL | | 0.0 | Lower limit for the control signal before manual override |
| **udiAbsTime** | UDINT | 10s … 600s | 180s | Duration of the anti-blocking operation in seconds |
| **tAbsStartTime** | TOD | 00:00:00 - 23:59:59 | 08:00:00 | Time of the anti-blocking operation |
| **eAbsDay** | eDoW | eDow\.Inactive, eDoW\.Monday … eDoW\.Sunday | eDoW\.Monday | Weekday of the anti-blocking operation |
| **rManValue** | REAL | | 0.0 | Manual override: manual value |
| **eManModeN** | eMANNUM | eMANNUM.Auto, eMANNUM.Man | | Manual override: operating mode |
### Function description
#### Control signal before manual override *rAA*
The control signal before manual override *rAA* is influenced by the anti-blocking module.\
The anti-blocking module is parameterized by the setpoints/parameters *udiAbsTime*, **tAbsStartTime** and **eAbsDay** as input signal the position feedback from the control valve *rU* is used.\
The minimum change of the valve position to lock the anti-blocking function is fixed at 10.0%.\
The control signal before manual override *rAA* is limited by the two absolute limits **rAbsMinLimit** and **rAbsmaxLimit** is limited.\
The position feedback from the control valve *rU* may be replaced by the control signal from the controller *rY* if no position feedback is available.
#### Control signal after manual override *rHA*
The control signal after manual override *rHA* is influenced by the output of the anti-blocking module, the control signal from the controller *rY*, the manual override and the forced control.
| **eManModeN** | Anti-blocking process | *xForce* | **xForceOption** | *rHA* | Notes |
| ------------- | --------------------- | -------- | ---------------- | ----------------------------------- | ------------------------------------------------------ |
| eMANNUM.Auto | FALSE | FALSE | X | *rY* | Automatic operation with passive anti-blocking process |
| eMANNUM.Auto | TRUE | FALSE | X | Output of the anti-blocking process | Automatic operation with active anti-blocking process |
| eMANNUM.Man | X | FALSE | X | **rManValue** | Manual override |
| X | X | TRUE | FALSE | 0.0 | Forced override 0.0% |
| X | X | TRUE | TRUE | 100.0 | Forced override 100.0% |
Legend: X = any
#### Position monitoring
The position monitoring can be enabled (**xControl** = TRUE) or disabled (**xControl** = FALSE).\
When position monitoring is enabled, the absolute value of the difference between the control signal after manual override *rHA* and the position feedback from the control valve *rU* is determined and compared with the threshold **rControlDiff** .\
If this difference permanently exceeds the threshold during a reporting delay **udiControlTime** an alarm signal is generated, provided at the same time the feedback - automatic operation *eAO* signals automatic operation (*eAO* = HVACTYPES.eManNum.Auto).\
This alarm signal is passed to the output *xAlarmPos* ( *xAlarmPos* = TRUE).\
The alarm signal is deactivated again (*xAlarmPos* = FALSE) as soon as the difference falls below the threshold for the first time.
#### Position feedback from the control valve *rU*
The position feedback from the control valve *rU* may be replaced by the control signal from the controller *rY* if no position feedback is available.
#### Anti-blocking module
The anti-blocking module is implemented by the numerical anti-blocking module with adjustable duration (FB: AbsA).\
The duration *udiAbsTime*, the time **todAbsStartTime** and the weekday **eAbsDay** are adjustable.\
The minimum runtime to lock the anti-blocking operation is 30s.\
The timestamp (date / time) of the last anti-blocking operation *dtAbsLastOn* is available.
#### Aggregate fault *xAlarm*
The aggregate fault *xAlarm* is activated (= TRUE) if *xAlarmPos* or the input *xAlarmIn* is active.\
In all other cases the collective fault is *xAlarm* is not activated (= FALSE).
#### Collective automatic-mode message *xAuto*
The collective automatic-mode message *xAuto* is activated (= TRUE) if the input *eAO* has the value HVACTYPES.eManNum.Auto and the setpoint / parameter **eManModeN** contains the value eMANNUM.Auto.\
In all other cases the collective message is automatic operation *xAuto* is not activated (= FALSE).
#### Forced override *xForce*
The forced override acts directly on the output *rHA*. The parameter **xForceOption** determines which state the output *rHA* assumes when TRUE at the input *xForce* takes.\
\
At **xForceOption** = FALSE\
If the input *xForce* is TRUE, then the output *rHA* is set to 0.\
\
At **xForceOption** = TRUE\
If the input *xForce* is TRUE, then the output *rHA* set to 100.
### CODESYS
InOut:
| Scope | Name | Type | Initial |
| ----------- | ----------------- | ------- | ----------------- |
| Input | `rY` | `REAL` | |
| Input | `xForce` | `BOOL` | FALSE |
| Input | `xAlarmIn` | `BOOL` | FALSE |
| Input | `rU` | `REAL` | 0 |
| Input | `eAO` | eManNum | eManNum.Auto |
| Input | `rPoti` | `REAL` | |
| Output | `rHA` | `REAL` | |
| Output | `rAA` | `REAL` | |
| Output | `xAlarmPos` | `BOOL` | |
| Output | `dtAbsLastOn` | `DT` | |
| Output | `xAlarm` | `BOOL` | |
| Output | `xAuto` | `BOOL` | |
| Input Const | `udiControlTime` | `UDINT` | 200 |
| Input Const | `rControlDiff` | `REAL` | 7 |
| Input Const | `xControl` | `BOOL` | TRUE |
| Input Const | `xForceOption` | `BOOL` | TRUE |
| Input Const | `rAbsMaxLimit` | `REAL` | 100 |
| Input Const | `rAbsMinLimit` | `REAL` | 0 |
| Input Const | `udiAbsTime` | `UDINT` | 180 |
| Input Const | `todAbsStartTime` | `TOD` | TIME\_OF\_DAY#8:0 |
| Input Const | `eAbsDay` | eDoW | eDow\.Monday |
| Input Const | `rManValue` | `REAL` | 0 |
| Input Const | `eManModeN` | eMANNUM | eMANNUM.Auto |
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