| Description: |
| A Processing Object that detects when an Object's Value property has changed. The oChanged Object takes the Value property of the Object to which the Input property links and compares it to the Value property of the Object to which the Output property links. Once the comparison is made, the input value is copied to the output value. |
| Operation: |
| | The oChanged Object takes the Value property of the Object to which the Input property links and compares it to the Value property of the Object to which the Output property links. If the two values are different, then the Changed property is set to 1; otherwise, it is cleared to 0. After the comparison is made, the input value is copied to the output value. If the input value does not change by the next time that the oChanged Object evaluates it, then the Changed property will have been set to 1 for one Object list loop. Normal operation of the oChanged Object is to take the input value and compare and copy it to the output value once every Object list loop. If the property option "C" is used then the operation is modified so that this function only occurs once each time the Flag-property pointed to by the ClockIn property transitions in the manner specified by the InvertC property. An 8-Bit signed Value property can be substituted for the Output property by specifying the appropriate property option. |
| Property Options: |
| | The oChanged Object has 4 variants which are selected with the 2 property options: O and C. - O specifies that the Output property is replaced with a Value property.
- C specifies that the ClockIn and InvertC properties are added.
| | Continuous
operation | Clocked
operation |
|---|
| Pointers for both input and output: |  | oChanged |  | oChangedC |
|---|
| Signed 8-Bit Value on output: |  | oChangedO |  | oChangedOC |
|---|
|
| Storage size & Availability: |
| | The following table lists the size and availability of the oChanged Object and its variants:| Object | Size | Version |
|---|
| oChanged | 3 Bytes | B.1.0 | | oChangedO | 4 Bytes | | oChangedC | 5 Bytes | | oChangedOC |
|
| Properties: |
| The following table lists the Properties of the oChanged Object: | Address | Returns a pointer to the address of the oChanged Object instance. Data-Type: Address, Read-Only Data-Range: 0 - 127 | | Changed | A value that indicates if the value of the input object has changed. Data-Type: Bit, Flag Data-Range: 0 - 1 | Value | Constant | Description | | 0 | cvFalse | The value of the input Object has not changed since the last Object list loop | | 1 | cvTrue | The value of the input Object has changed since the last Object list loop |
| | ClockIn | A pointer to an Object's flag property that will be used to determine when the Object performs its function. Data-Type: Flag-Pointer Data-Range: 0 - 127 Availability: oChangedC oChangedOC | | Direction | A value that indicates if the change was greater than or less than the previous value. Data-Type: Bit, Flag Data-Range: 0 - 1 | | Input | A pointer to an Object whose value will be monitored for change by comparing it to the value of the Output object. Data-Type: Number-Pointer Data-Range: 0 - 127 | | InvertC | A value that specifies the active transition state of the flag property to which ClockIn points. Data-Type: Bit, Flag Data-Range: 0 - 1 Availability: oChangedC oChangedOC | Value | Constant | Description |
|---|
| 0 | cvFalse | The compare and copy function is performed when the Flag property to which the ClockIn property links transitions from 0 to 1 |
|---|
| 1 | cvTrue | The compare and copy function is performed when the Flag property to which the ClockIn property links transitions from 1 to 0 |
|---|
| | Operate | A value that specifies if the evaluation will take place. Data-Type: Bit, Flag, Default Data-Range: 0 - 1 | | Output | A pointer to an Object whose value will be used to track the last value of the Input object. Data-Type: Number-Pointer Data-Range: 0 - 127 Availability: oChanged oChangedC | | Value | A signed 8-Bit value that can be on the output of the oChanged Object. Data-Type: Byte Data-Range: -128 to +127 Availability: oChangedO oChangedOC |
|
| Example: |
| | In the following example, a Virtual Circuit is created that uses the oChanged Object to detect when a different key on a keypad has been pressed. When it detects this, a short tone is produced.
' When different buttons on a keypad
' are pressed, Make a short sound.
Dim C As New oChangedO
Dim K As New oKeyPad
Dim B As New oBusIC
Dim Y As New oCountDownO
Dim T As New oTone
Dim W As New oWire
Sub Main()
K.Operate = cvTrue
C.Input.Link(K)
C.Operate = cvTrue
B.Value = 6
B.ClockIn.Link(C.Changed)
B.Operate = cvTrue
B.Output.Link(Y)
Y.ClockIn.Link(OOPic.Hz60)
Y.Operate = cvTrue
W.Input.Link(Y.NonZero)
W.Output.Link(T.Operate)
W.Operate = cvTrue
T.Value = 120
T.IOLine = 24
End Sub
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| See Also: |
| | oBus - An Object that copies values from one Object to another. |