I thought it would be harder than this

[bernie_carlton]

Comments?

I have two offline RSLogix5000 programs for the same system.

#1 is a previously saved copy of the running program but now modified with 'improvements'.

#2 is a recent copy of the currently running program with relatively current data values.

I want to transfer critical data table information from the #2 copy into the #1 'modified' copy. (Rather than download the 'modified' copy and have to reenter the critical data, a lengthy task. It happens to be a substantial array of a complex UDT.)

What I did was opened the #2 program, right click on the data tag in 'Controller Tags' (in 'Edit Tags') and selected 'copy'. Then I went to #1 program to the bottom of the 'Controller Tags' at the point where a new tag could be created, right clicked and chose 'paste'. It created a new entry but objected that it had the same name as another tag (it does) and appended a '1'. But it seems to have all good up-to-data values.

So far I'm intrigued but not concerned.

Now I right clicked on the original array in #1 program and 'delete' was an option! I guess it would only be disabled if online. I deleted the tag. But now any rung which had logic accessing members of that tag were in error ('e').

Now I went to the newly added tag, edited the name deleting the appended '1'. Everything is accepted.

Has anyone done this? As the title of this thread mentions I thought it would be harder than this. Am I fooling myself?

 

[sparkie]

I think you got it right. The cool thing about the tag based system is that you create "pointers" to the actual memory addresses. Your logic was looking for a non-existent tag, and I would expect there to be an error if it was referencing data that was not there.

Now once you pasted the tag back in with the values you wanted, the logic is pointing to a tag that IS there. Sounds perfectly logical to me. I'll have to try that when I get to work tomorrow.

 

[keshik]

I would agree.

You can do something similar to change alias' at run time. Change the wrongly-aliased tag name, create a new tag with the proper alias (and the old tag's name), correct the name of the tags in the logic back to the original tag name, and then delete the old, wrongly-addressed tag that is no longer used in the logic.

 

[Phil Buchanan]

It is that easy. Logix is a very powerful and very open system as far as restrictions are concerned and this can be a great thing in the hands of an experienced person and very dangerous in the hands of the inexperienced.

It will let you do very powerful things as you have found with little effort but you can also do lots of damage with little effort also. I think because it's less restrictive people moving from RS Logix 5 or 500 have a hard time making the transition successfully.

 

[ASF]

I've done basically that same thing, it really is that simple! In fact you can make it even simpler - just delete the original tag before you paste the updated one in, and you don't even have to bother renaming!

It is that easy. Logix is a very powerful and very open system as far as restrictions are concerned and this can be a great thing in the hands of an experienced person and very dangerous in the hands of the inexperienced.

It will let you do very powerful things as you have found with little effort but you can also do lots of damage with little effort also. I think because it's less restrictive people moving from RS Logix 5 or 500 have a hard time making the transition successfully.

That's what I love about AB. It doesn't try too hard to protect you from yourself - it assumes you know more or less what you're up to and just rolls with it. As contrasted to some of my experiences with Siemens, where when creating an ADD instruction and specifying INT tags for all three operands, it still gave me a compile error until I specified what type of operand the ADD instruction was to work on. Yes, AB can be dangerous in the hands of the wrong person, because it lets you do more or less whatever you want - but if it's me pushing the buttons I'll take that any day over the "but what data type is this ADD instruction with three INT's defined in it operating on?"

 

[sparkie]

I'm a fan of Logix5k myself. I love being able to write out logic not knowing what the IO is actually going to be yet.

And I take that approach to anything with our controls. I told management when documenting out plant systems I was not going to write it for the lay. Anyone using a laptop to get on our systems better have a clue what they are doing .

 

[Phil Buchanan]

That's what I love about AB. It doesn't try too hard to protect you from yourself - it assumes you know more or less what you're up to and just rolls with it. As contrasted to some of my experiences with Siemens, where when creating an ADD instruction and specifying INT tags for all three operands, it still gave me a compile error until I specified what type of operand the ADD instruction was to work on. Yes, AB can be dangerous in the hands of the wrong person, because it lets you do more or less whatever you want - but if it's me pushing the buttons I'll take that any day over the "but what data type is this ADD instruction with three INT's defined in it operating on?"

I agree 100% I am a Logix5K fanboy also and prefer it over any other PLC platform and I have used them all and worked for a couple but I was also just bringing awareness to the fact that it's a double edged sword and can be a start to creating a PITA program or even dangerous in the wrong hands.

Kinda like the Force.