Indirect Addressing Emerson PAC Machine Edition

[James42005]

Howdy folks, I am an Allen Bradley guy currently living in an Emerson world. Working with Rx3i on PacSystems Machine Edition v. 9.6? i think?

What I need to do is search an array of bools for any non-zero value. I don't really care which element it is, only if any are = 1.

So, in AB land I would probably use indirect addressing to index through the array to find any bool = 1.

Im struggling to find an option for how to do this in my new life as a GE/Emerson guy.

Thanks

 

[Steve Bailey]

Check out the SEARCH_GT instruction, using a target of zero. It will check over a range of variables and return a boolean true if it finds a match. It will also return the location of the first nonzero variable in the range, all within a single scan. If you're using addressed variables, be aware that you can assign the same address to a BOOL array and a WORD array. So if you have a BOOL array of 128 elements that starts at %M00001, you can also define a WORD array of 8 elements starting at %M00001.
The Rx3i also supports indirect addressing, so the techniques you've learned in Rockwell land may also work.

 

[James42005]

Thanks Steve,

I looked into the search instructions... it doesn't appear they are available with bool data type arrays.

Byte, dint, sword, int, unit, and word

 

[Steve Bailey]

I looked into the search instructions... it doesn't appear they are available with bool data type arrays.

Here's how I would approach it.
If your BOOL array doesn't already have an address assigned, give it one. Let's say its 256 elements in the array and you assign it to the address %M00097. Now you can define a WORD array of 16 elements, assign it the same starting address of %M00097 and use that array as your search range. The only thing to watch out for is that the starting address you assign to your BOOL array must lie on a byte boundary. That means when you divide the address by 8, there must be a remainder of 1. Examples are %M00001, %M00009, %M00017, etc. When you assign a memory type that is inherently BOOL like %M to a WORD data type, the software will automatically assign it to a byte boundary. When you try to assign %M00005 to a WORD variable, the software will change it to %M00001.