Indexing Example
Consider Grablink Value. This board owns 8 input designators, and 3 output designators. Each of them in their respective input or output set is assigned an index.
Index assignment
I/O line |
Status |
Input designator |
Index |
Output designator |
Index |
TRG |
Input only |
TRG |
17 |
- |
- |
STR |
Output only |
- |
- |
STR |
17 |
A1 |
Input or Output |
A1IN |
28 |
A1OUT |
28 |
A2 |
A2IN |
29 |
A2OUT |
29 |
|
CK |
Input only |
CK |
20 |
- |
- |
LVAL |
LVAL |
21 |
- |
- |
|
FVAL |
FVAL |
22 |
- |
- |
|
DVAL |
DVAL |
23 |
- |
- |
|
SPARE |
SPARE |
24 |
- |
- |
The index #17 addresses 2 different physical pins, one in the input table and another one in the output table. As an input designator, this index points to "TRG" located on pin 8 of SYSTEM connector. As an output designator, this index points to STR located on pin 9 of SYSTEM connector.
On the other hand, the index #28 always points to the same physical pin because it is a bidirectional I/O pin. In this example, as an input designator, this index points to A1 located on pin 6 of SYSTEM connector, and the same pin also as an output designator.
The index will be used as a pointer for several collection parameters belonging to the board object.