A PLC usually consists of several PLC cards, each of which may contain a different number of PLC connection points in the form of inputs and outputs. A PLC card is represented in EPLAN using a PLC box, where a physical PLC card can be placed distributed over several schematic pages. In this case, there are then several PLC boxes with the same device tag that are actually all part of a single PLC card. For example, a PLC card with 32 inputs can be displayed on four pages, with a PLC box with eight inputs being drawn on each page.
For distributed display of PLC cards, the so-called PLC card overview eases the process of finding PLC connection points within the schematic. It represents the physical cards of the PLC, which are represented in the distributed schematic view by the individual PLC boxes. It graphically displays which inputs / outputs are occupied and which are available, which actuators and sensors they are connected to, and on which schematic page they are displayed. This type of overview can contain a different number of inputs and outputs, depending on the manufacturer and type. You draw PLC card overviews on pages of type "Overview". A synchronization in the form of cross-references occurs between the PLC card overview and the schematic pages. The PLC cross-reference then points to its reference in the overview page and vice-versa.
In order for EPLAN to create and display PLC cross-references between a PLC connection point in the schematic and a PLC connection point in the overview, the following properties of both connection points on both pages must agree:
- DT of the PLC card
- Function definition
- Plug designation
(For bus ports: Bus interface name + Plug designation) - Connection point designation.
Note:
The PLC address does not provide identification and has no importance in the formation of cross-references.
Create cross-references between PLC connection points
Preconditions:
- You have opened a project.
- You have created a multi-line schematic page.
- You have created a page of type "Overview".
- You have selected all the check boxes in the Display overview cross-references group box under Options > Settings > Projects > "Project name" > Cross-references / contact image > Display.
- Open the multi-line schematic page in the graphical editor.
- Select the menu item Insert > Box / connection point / mounting panel > PLC box, and draw the PLC box that represents the PLC card as a rectangle.
- In the Properties <...> dialog enter the device tag of the PLC card in the Displayed DT field and click [OK].
- Open the overview page and draw a PLC box representing a PLC card.
- In the Properties <...> dialog enter the same device tag as the PLC card on the schematic page and click [OK].
- Select the menu item Insert > Box / connection point / mounting panel > PLC connection point (DI) and place a PLC connection point inside the PLC box in the overview page.
- In the Properties <...> dialog of the PLC connection point, enter the connection point designation and click [OK].
- Open the schematic page and insert a PLC connection point within the PLC card.
- In the Properties <...> dialog, enter the same connection point designation as for the PLC connection point on the overview page.
Both PLC cards now "inherit" the PLC connection point device tags, since the connection points are located within the drawn boxes. Since the DT, connection point designation, and function definition of both PLC connection points are identical, EPLAN creates cross-references between both connections and displays them at the components in the schematic and in the overview page. - Open both pages in separate editors to observe the cross-reference display.
The PLC connection point -A1:1 in the schematic (left side of the illustration) points to the PLC connection point -A1:1 in the overview page (right side of the illustration) and vice-versa. The address I1.0 has no effect on the cross-reference creation.
See also