TOP Server Controllogix L5K Import of PID

TOP Server ControlLogix L5K Import of PID.CTL Tags By Colin Winchester, Software Toolbox Inc.

When using the TOP Server with the ControlLogix Ethernet Driver you can link to a RS Logix 5000 L5K file. This file can be used to automatically generate the Tag Database in the TOP Server. This saves a great deal of time as well as avoiding potential errors during data entry. While this is a great feature, one of the drawbacks is that all the ControlLogix tags are potentially brought into the Tag Database of the Server and many of these tags are not needed in the majority of situations.

When a PID function block is set-up in the ControlLogix one of the addresses that is created is the .CTL tag. This tag is a double-integer and is called …[PIDstructurename].CTL in the RS Logix5000 program. The bits in of this double-integer are used as part of the PID program. Under the double-integer .CTL tag there are also Boolean tags created for each of the 32 bits of the .CTL tag. These tags are simply added under the .CTL tag with the addition of a “.”, then the number of the bit 0-31. There are additional tags added to the PID structure that set or clear these bits in the .CTL tag. These tags all reside at the same “file folder” level (see RS Logix 5000 help file under PID structure for details on these tag names and purpose). Since the same bits are being accessed from two different tagnames in the ControlLogix, the TOP Server only brings the group at the same level into the Server’s Tag database. There are basically two reasons for this, 1) it helps limit the total number of tags in the database, 2) using the “higher-level” tags increases communications performance (see White Paper on Optimizing the ControlLogix from Software Toolbox for more information).

While these .CTL Boolean tags are not generated automatically by the Server it is easy to add them to your tag database if needed. Step one is to add a new group in the Server’s Tag Database under the particular PID structure of concern. Name this new group “CTL.” Next find the [PIDstructurename].CTL tag under the PID folder in the Tag Database. Highlight this tag and right-click with the mouse and select copy, then right-click on the new group you created and select paste. Now open the CTL folder and double-click on the tag you just pasted in the group and the tag properties window will open. Change it’s data type to Boolean and add “.0” to the tag address field. Finally add a zero to the end of the tagname and hit apply. The next step is to simply hit the Icon in the tag properties window that has two tags (meaning copy) 31 times and watch the tagname and address field increment automatically. This is a simple process that takes a short amount of time, but will result in the addition of the CTL.bitvalue tags being added to your project.