A frequent contributor on the forum posted a question recently that I thought I would answer here in detail.
In the circuit below function text is assigned to the relay coil. The designer would like to transfer this text automatically to both the Coil, the coil contacts and the related lamp which is part of the circuit. For this example they will all be located on the same schematic page but of course the contacts and the lamp can also be anywhere in the design.
I was so inspired about this topic I created a video and posted it on You Tube.
The function text at the bottom is a special kind of text know as Path Function text, this text can be accessed directly in the schematic and its data can be transferred easily to other objects in its path, for IEC designs this requires vertical alignment and for NFPA this requires horizontal alignment.
I will start by creating the path function text below the relay coil and by adding a display property to the coil to display the text there.
Now to define the coil and the contact as related all I need to do is assign them with the same device tag (DT) or reference designator. While I am doing that i will also add the display property for the Function Text. This data will be available directly at the contact because when I assign the DT, they will be defined as related functions of the same logical device.
Ok, so now all we have left is the lamp..how do we access the data of the relay?
Block Properties
The lamp and the contact are related though a logical (wired) connection. In EPLAN we can make use of these direct and indirect relationships by creating a custom data property known as a Block Property. I will avoid trying to define what a block property is, I will leave that to EPLAN, but I will state that they are a powerful tool available to communicate information in EPLAN to devices that share some type of logical relationship.
In the case of the contact and the lamp they are logically related via the connection point X2 on the lamp and the N.O. contact. EPLAN is aware of this relationship via the connection (wire) and you can use this relationship to access information about the relay contact via this connection. In essence EPLAN will look out from the connection (H23:x2) to the next device and you can tell EPLAN to make information about that device available at the lamp.
Block Properties at the Part Reference level
Block Properties can be created at two different levels, at the symbol or object reference level or at the project level. I like to first create them at the symbol level to make sure that they work and then copy them to the project level. At the symbol level we have access to specific data values that makes the creation process much easier.
This means that we can create a block property locally for this instance of the lamp symbol and any copies that we make of it, but if we insert a new lamp symbol using symbol insertion, that data format will not transfer because the definition was created in the schematic for a particular instance of the symbol. To make the block property available to ALL symbols in the project we need to define the block property at the Project Level AND then assign it at the schematic level as a display property.
Are you starting to think about local and global variables? Good, because that is essentially exactly what we are talking about.
Block Property Format
We will begin by defining the relationship between the objects and the data, this is known as a block property format.
We will open the device properties of the lamp.
On the first properties tab (Signal Lamp) we will look at the properties in the grid at the bottom of the dialog. Let’s start by looking for existing Block Property formats and find an available slot.
I will be creating a new Block Property: Format at position #10, you may already have some in your project so if #10 is already in use just select another position and make note of it.
Once you create the block Property Format you will be returned to the main dialog
Selecting the Value field of the new property, the ellipsis should appear […] and we want to select that to define the format of this block property.
A new dialog will appear: “Format”
We will now look for the data that we wish to display on the related object
First I should tell you that the current data displayed is related directly to the Signal Lamp that we selected and we can verify that by looking at the Navigation dialog at the bottom.
The relay contact is related to the lamp via a connection at H23:x2
So starting at the point of view of the lamp, we want to look at data related to a Target (some other object) via a connection point on the lamp.
In the available format elements select: “Target via connection point and target number”.
A list of connection points will appear, and the lamp has two connection points so we should expect to see data at two connection points. Looking “out” from the connection point along the wire we see a relay contact (Connection point 1: Target 1) and we see a terminal (Connection point 2: Target 1). This information helps to confirm that I am looking at the correct data and I also know which connection point I want to use as a reference.
Again, the current list of available format elements (data) is for the lamp and we want them to reflect data for the contact or the coil.
To change the focus of the data set, we will need to navigate up the connection point to the contact.
So I will select Connection Point 1, Target 1, and then at the bottom I will select the “UP STAIRS” icon to “navigate” to the change-over contact.
When I do, the information in the navigation pane will update describing where I am:
I started at the Lamp and I am now referencing a target via a connection point (Change-Over Contact)
Ok great, we can now get the data from the contact or with a few more clicks directly from the coil because they are directly related.
In the middle of the list of format elements we can see a property “Main Function (=+K10 A1/A2 Coil for Power Contactor) or similar.
If we select this property and then select the Navigation tool again, we can change the focus to the main coil. Again, we can verify this by looking in the navigation pane at the bottom. It reads as follows top to bottom:
- We started at the lamp
- We jumped to the next target (relay contact) via a connection point
- We then jumped to the main function which is the relay coil.
The available format elements will now reflect data for the relay coil.
Ok great, we can now point to the data from relay coil.
In the “available format elements list” I will scroll to the top and expand the function list.
This is a list of data types associated with the Relay Coil.
I will now select the General Function element and then to blue arrow icon to expand and access related data sets.
I will search for function text..and in this case I can see the desired value in Function Text Common, which I will select.
Now in the right side of my format dialog I will see the selected data element and in the bottom right preview window I will see a Block Property (Format?) and a preview of the desired results.
Now this is why I like to create these at the part reference level first so that I can see the specific data that I want, you can create these at the project level but you will not see any object specific data.
[OK] to save the BP
We will test this first and later we will copy this (BP format ?) to the project level.
Returning to the schematic the BP format has been created and we should see it in the properties list.
To see it we need to add it as a display property to the lamp.
The result is a circuit where the three dependent function texts can be automatically synchronized to the main path function text, no matter what page the contact and lamp find themselves on.
To update the text after an edit, go to Project Data > Connections > Update.
WARNING:
Changing the orientation of the lamp in the circuit will affect the transfer of data to the lamp. Computers are excellent rule followers; In my case I told EPLAN to look out the connection point of the lamp at x1 to the next device; if i insert the symbol rotated 180 degrees it will not “see” the contacts but instead the terminal X1:4.
Almost Done.. Now we need to copy the BP to create one with global project scope.
Project Level Block Property
Lets open up the local block property that we created and copy the Format or Value.
Simply select the value and copy
Close the dialog
Project > Properties
On the Properties tab sort by property name by double clicking the column heading.
Look for a list of Block Properties
I will be randomly creating one at: Block Property: Format (General Devices) [10]
I would simply look for one that has NOT already been used.
Add the property as NEW if needed.
When the value window appears simply paste the previous data into the cell.
OK to save and close the dialog
Return to the schematic editor
Open the properties of the lamp
Delete the block property that we previously created as we don’t need it anymore.
Click the cell to delete the text
Once the text is gone you can click and delete again to remove the cell.
Go to the display tab
Verify that the Block Property is assigned