Eplan has a functionality called “PLC Tracking” that allows to track a signal to/from a PLC input or output.
This is used, for example, when numbering devices based on PLC data. One might use the PLC address as the Device Tag for a relay.
This functionality can be used for other purposes once we understand how it works.
On LinkedIn, one of the EPlan group members asked how to get data from the last terminal connected to another terminal without taking in-between terminals into account. A simplified version of this would be:
Here we have a black box on the left, three terminals in between, and a final black box on the right. For the sake of this example, we assume that U1111 & X4 are within the same enclosure, that X5 is located in a field mounted junction box, and that X6 & U2222 are in a remote enclosure.
Using the PLC tracking, we can display properties from the last connected target under X4 and X6. For this we would use a Block Property Format on both X4:1 and X6:1 like so:
X4:1, Block Property Format 1: [20025,1,1<20201<20048,1,0,0,0,0,0,0,0,en_US,0,0,0,0,0,0>>] X6: 1, Block Property Format 1: [20025,2,1<20201<20048,1,0,0,0,0,0,0,0,en_US,0,0,0,0,0,0>>]
These block properties can be described as “Start from Terminal, then take the Last function via connection point and target number (PLC), Connection point 1, Target 1, and finally take the Device tag”
Since the default display properties on terminals will display Block Property 1, then we should automatically see the result as shown in Image 1.
All good, but our LinkedIn user would like to get properties from the last terminal, not the last device. This is where we can “cheat” Eplan into doing what we need.
When looking at X4:1 properties, under “Symbol / function data”, we have the “Logic…” button:
This button brings up the following dialog:
We see here the “Target tracking (PLC) to” property for each connection point of the terminal. We are interested in stopping the tracking between pins 1 & 2 (pins 3&4 are used for jumpers so they are not of interest for now). To do so, simply delete the values in columns 1 & 2 as so:
We also do the same for terminal X6:1, and we refresh the connections by clicking this toolbar button in Eplan’s main toolbar:
We should now see this:
Notice that the tracking is now stopped at the outer most terminals and that the desired information is displayed. We could now display that Block Property on a terminal diagram report.