MCV_GrpSingleAxSelect
This FB is a utility FB which can be used in a PLC application.
With reference to a currently selected axis, it is used to select the previous or next axis from the list of axes contained in the axis group. The result is accessible at the FB both as a Boolean value and a binary encoded value. In addition the output conforming to PLCopen is supported as IDENT_IN_GROUP_REF.
Block diagram
FB parameters
VAR_IN_OUT | ||
Variable name | Data type | Description |
AxesGroup | AXES_GROUP_REF | Axis group reference |
VAR_INPUT | |||
Variable name | Data type | Description | |
Enable | BOOL | If TRUE is indicated at the input, rising edges are evaluated at the “Next” and “Previous” inputs and the value is considered at the “InitChAxIdx” input. | |
Next | BOOL | A rising edge has the result that with respect to the axis just selected, the next axis present in the axis group is detected and the corresponding output is set to TRUE. In this context the next axis means an axis with a higher index than the sequence criterion in the list of axes present in the axis group. | |
Previous | BOOL | A rising edge has the result that with respect to the axis just selected, the previous axis present in the axis group is detected and the corresponding output is set to TRUE. In this context the previous axis means an axis with a lower index than the sequence criterion in the list of axis present in the axis group. | |
InitChAxIdx | INT | Index of the axis in the axis group (channel) which is selected after the “Enable” input was set to TRUE the first time. | |
-1 | no output is selected | ||
0 | “AxisAct_0“ output becomes TRUE | ||
… | … | ||
15 | “AxisAct_15“ output becomes TRUE | ||
VAR_OUTPUT | ||
Variable name | Data type | Description |
Valid | BOOL | TRUE when the inputs are evaluated. |
IdentInGroupRef | IDENT_IN_GROUP_REF | Reference to the assignment of an axis in an axis group. |
AxisSelChgd | BOOL | Is TRUE for one PLC cycle when selection has changed and therefore the value changed at the “SelAxisBits” output. |
AxisAct_0 | BOOL | TRUE indicates the axis in an axis group which is the previous or next axis. |
… | ||
AxisAct_15 | ||
SelAxisBits | WORD | Displays the successful selection as binary value. |
Behaviour of the FB:
- On a rising edge, the “Prev“ and “Next“ inputs cause a change in the outputs.
- The FB considers the option that the axes in an axis group may be assigned any position and the list of the axes in an axis group may contain gaps.