Indirect Addressing

I'm converting a program from RS500 up to Studio5000. As an example, an address in RS500 like N133:80.1 is being created in Studio as a Tag N133 with an array of 80 DINTS. We then call that address within the Studio program 133[80].1.

All is fine until I came across some indirect addressing in RS500,

N87:[N137:2]

If I were to convert this into our Studio format it would be N87:[N137[2]]. This however does not work, I get "Invalid expression or tag" or "Invalid array subscript specifier." Any suggestions on how to format the indirect addressing? Any instructions that could be used?

Thanks for the help!

And this is why I really hate conversions...

Surely it's a typo from you, but shouldn't it be N87[N137[2]]? Without the :

You have to get rid of the ":", you are no longer working with Memory files, just arrays.

Try: N87[N137[2]]

BTW, I hate it when folks do conversions like this, re-using the old platform memory scheme. It's like your mule died, so you buy a new truck to pull your wagon.

You can't use nested square brackets.
You need to use a dummy tag:
MOV N137[2] Dummy
Then you can use N87[Dummy]

I had already tried eliminating the ":" but that also doesn't work

I don't have a choice in how its re-tagged, the customer gets what they want

Contr_Conn said:

You can't use nested square brackets.
You need to use a dummy tag:
MOV N137[2] Dummy
Then you can use N87[Dummy]

Click to expand...

A co-worker showed me this method, which works. I was just hoping there was a cleaner way of doing it. This may have to be the option though

derrickjp7 said:

I'm converting a program from RS500 up to Studio5000. As an example, an address in RS500 like N133:80.1 is being created in Studio as a Tag N133 with an array of 80 DINTS. We then call that address within the Studio program 133[80].1.

Click to expand...

N133:80 is the 81st element of that Integer file, the index starts at zero, so the conversion (if that was the last Integer) would have created an array of 81 DINTs, 0 thru 80.

You have to be ultra careful with conversions. Notice how it created a DINT array, not an INT array ?

Those INTs in the logic are signed integers, and if you inspect bit 15 to see if they are negative (very common, its cheaper than a LES instruction), then the conversion to DINTs will have shifted the sign bit to bit 31, so it won't work.... Lots of other things to be wary of, as well.