declaration of variables?
- Thread starter mrnicks
- Start date
What PLC platform ?
In Siemens STEP7 you have FBs and FCs for "reusable code". It is possible to declare variables in the FCs and FBs. The declared variables are used in the code part of the FBs and FCs.
In Siemens STEP7 you have FBs and FCs for "reusable code". It is possible to declare variables in the FCs and FBs. The declared variables are used in the code part of the FBs and FCs.
Yes, FB function blocks in Siemens is used to write reusable code where you declare variables that is used inside the FB.
I dont know the function blocks in Allen Bradley, but I think that it is a somewhat different concept. However, I am sure that you declare variables in a similar if not exactly the same way.
I dont know the function blocks in Allen Bradley, but I think that it is a somewhat different concept. However, I am sure that you declare variables in a similar if not exactly the same way.
CapinWinky
Member
Rockwell, as is there way, uses different terminology from the reset the world. So, while any computer programmer or controls engineer for a different platform would call it declaring a variable, Rockwell calls it creating a tag. So, your tag lists are Rockwell's version of a declaration of variables. I'm kind of curious what they call it in the Yaskawa world.
In a lot of platforms (including everything based on Codesys), you can define the variables in the Structured Text standard format like this:
MyBool : BOOL;
MyInt : INT:=5; (*I initialize this INT to 5 on startup*)
MyArray : ARRAY[0..9] OF INT; (*an array of ints*)
In a lot of platforms (including everything based on Codesys), you can define the variables in the Structured Text standard format like this:
MyBool : BOOL;
MyInt : INT:=5; (*I initialize this INT to 5 on startup*)
MyArray : ARRAY[0..9] OF INT; (*an array of ints*)
This clears it up. I know tags. I just started with yaskawa motion controllers so I couldn't tell you just yet. I'm still learning everyday!
LadderLogic
Member
The answer for Yaskawa depends on if you are using an IEC version of the controller or an original one.
The former is IEC61131-compliant so you would have to declare all the variables in a standard way using VAR...END_VAR (and the related) blocks.
The latter is a traditional address-based PLC so no declaration would be needed.
LadderLogic
Member
Then there is no decalring variables. You may create variable names just for your convenience.
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