# 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 |