Rockwell Control Logics Tags

I am tring to learn basic programming in control logics and I have been making different kinds of tags to get the hang of it. In the example program I am following through some of the tags use a period . Like this example TIMS.High_Level but when I make a new tag and try to use a period in it the software package won't let me do it?

Tim,

Usually when you see a tag with a period it means that tag is part of some sort of structure, like part of a User Defined Type (UDT) or part of an Add On Instruction (AOI).

So for the example you have given TIMS would be a UDT or AOI and High_Level is part of that UDT or AOI,

Mark

So I can't use a period in my tags

The period is a logical seperator. If it's just a readibility issue most use underscores.

Another use for a period is before a number 0-31 to reference a certain bit from a DINT.

Tim Ganz said:

So I can't use a period in my tags

Click to expand...

Not by itself, no. The period is a delimiter that indicates that the "thing" that follows the period is a "member" of what precedes it.

e.g., in one of our programs I created a data type called "position" that has 2 integers that correspond to the word and bit location in a bit array (each position in the machine has a bit to show the part status in that position, with about 70 positions). I can then create a tag describing the position of a tool, call it "Drill1Position" and its data type will be "Position". It will have 2 members, "Bit" and "Word". To use the bit address in code, I would use "Drill1Position.Bit". The part following the period ("Bit") is a member of the part preceding the period (Drill1Position).

Note that this convention can also be used to refer to an individual bit within a word. So if you have a DINT tag, call it "yourDint", and you want to check the status of bit 13, you would say "yourDint.13"