> For the complete documentation index, see [llms.txt](https://support.powerio.com/hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.powerio.com/hub/codesys-hvac/en/hvac-library/functionblocks/control/control2seq.md).

# Control2Seq

## `Control2Seq` (FB)

FUNCTION\_BLOCK Control2Seq

### Short description

> Sequence control with on/off thresholds for an analog input signal\
> The action direction (inverted / direct) is also adjustable.

### Representation

<figure><img src="/files/d26de1396012ff2afcaa0ce108af6437e47922b0" alt=""><figcaption></figcaption></figure>

### Interfaces

#### Inputs

| Name  | Data type | Value range | Initial value | Function           |
| ----- | --------- | ----------- | ------------- | ------------------ |
| *rIn* | REAL      |             |               | Analog input value |

#### Outputs

| Name | Data type | Value range | Initial value | Function             |
| ---- | --------- | ----------- | ------------- | -------------------- |
| *xY* | BOOL      |             |               | Binary output signal |

#### Setpoints / parameters

| Name                | Data type    | Value range | Initial value       | Function                                                                        |
| ------------------- | ------------ | ----------- | ------------------- | ------------------------------------------------------------------------------- |
| **rSwitchOffPoint** | REAL         |             | 3.0                 | Off threshold                                                                   |
| **rSwitchOnPoint**  | REAL         |             | 7.0                 | On threshold                                                                    |
| **eAction**         | eControlMode |             | eControlMode.Direct | Action direction of the sequence control (Inverted = heating, Direct = cooling) |

### Function description

#### Digital output *xY*

The digital output *xY* is influenced by the action direction **eAction**, the analog input value *rIn* and the two switching thresholds **rSwitchOffPoint** and **rSwitchOnPoint** affected.\
If the action direction eControlMode.Direct is selected, then the on threshold **rSwitchOnPoint** must be greater than the off threshold **rSwitchOffPoint** be.\
If the action direction eControlMode.Inverted is selected, then the on threshold **rSwitchOnPoint** must be less than the off threshold **rSwitchOffPoint** be.

| **eAction**           | *rIn*                                                      | *xY*      | Notes                                                                    |
| --------------------- | ---------------------------------------------------------- | --------- | ------------------------------------------------------------------------ |
| eControlMode.Direct   | *rIn* < **rSwitchOnPoint** and rIn\* > **rSwitchOffPoint** | unchanged | Action direction = Direct: Actual value does not exceed any thresholds   |
| eControlMode.Inverted | *rIn* > **rSwitchOnPoint** and rIn\* < **rSwitchOffPoint** | unchanged | Action direction = Inverted: Actual value does not exceed any thresholds |
| eControlMode.Direct   | *rIn* >= **rSwitchOnPoint**                                | TRUE      | Action direction = Direct: Actual value exceeds on threshold             |
| eControlMode.Direct   | *rIn* <= **rSwitchOffPoint**                               | FALSE     | Action direction = Direct: Actual value falls below off threshold        |
| eControlMode.Inverted | *rIn* <= **rSwitchOnPoint**                                | TRUE      | Action direction = Inverted: Actual value falls below on threshold       |
| eControlMode.Inverted | *rIn* >= **rSwitchOffPoint**                               | FALSE     | Action direction = Inverted: Actual value exceeds off threshold          |

### CODESYS

InOut:

| Scope       | Name              | Type         | Initial             |
| ----------- | ----------------- | ------------ | ------------------- |
| Input       | `rIn`             | `REAL`       |                     |
| Input Const | `rSwitchOffPoint` | `REAL`       | 2                   |
| Input Const | `rSwitchOnPoint`  | `REAL`       | 6                   |
| Input Const | `eAction`         | eControlMode | eControlMode.Direct |
| Output      | `xY`              | `BOOL`       |                     |


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