The Change Select function block checks whether the input values have changed compared to the last DDC cycle. If the value has changed, it sets the corresponding Boolean output to "true" for 1 DDC cycle. More than one output can be "true" if numerous changes are detected.
Figure 1: ChangeSelect - Function Block |
Figure 2: ChangeSelect - Property Sheet |
Figure 3: ChangeSelect - Logic Diagram
Inputs
Description |
|
Enable |
It is a Boolean point that is used to enable the block. If it is set to "false", there is no change and all outputs remain "false". If it is set to "true", activates the change detection. |
In A |
If this input changes from the previous DDC cycle, Out A becomes "true". |
In B |
If this input changes from the previous DDC cycle, Out B becomes "true". |
In C |
If this input changes from the previous DDC cycle, Out C becomes "true". |
In D |
If this input changes from the previous DDC cycle, Out A becomes "true". |
Table 1: Inputs of ChangeSelect Function
Output
Description |
|
Out A |
If In A changes from the previous DDC cycle, Out A becomes "true". The output is "true" only in the DDC cycle where the change is detected. A change to "null" or from "null" is a valid change. |
Out B |
If In B changes from the previous DDC cycle, Out B becomes "true". The output is "true" only in the DDC cycle where the change is detected. A change to "null" or from "null" is a valid change. |
Out C |
If In C changes from the previous DDC cycle, Out C becomes "true". The output is "true" only in the DDC cycle where the change is detected. A change to "null" or from "null" is a valid change. |
Out D |
If In D changes from the previous DDC cycle, Out D becomes "true". The output is "true" only in the DDC cycle where the change is detected. A change to "null" or from "null" is a valid change. |
Table 2: Output of ChangeSelect Function
Parameter
Description |
|
Out Save |
Master Sync Enabled : If you set it to "true" the last output will be set as output for one cycle after the controller restarts. The application can use it to return to the same state before the controller restart. Out: To enable or disable the Out Save feature. Out Equal Zero:To enable or disable the Out Equal Zero feature. |
Table 3: Parameter of ChangeSelect Function
If Block Enable is "true", change in any of the input value the concern output is set to "true" for a short while.
Figure 4: Example - ChangeSelect Function Block |
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Refer to General Description for general information about IRMN4 Function Blocks.