AB 32K Procesor vs 16K+Memory Module

Hi,

I have a piece of kit using an AB SLC 5/04 that I'm putting onto an Ethernet network. A new 5/05 16k processor has been purchased, but I need 32k of memory. Instead of buying a new 32k processor (~€2000), could I use the 1747-M13 64k User Memory Module (~€200) on the 16k processor to expand the memory? I'm thinking that there must be a disadvantage to this, otherwise why use the 32k or 64k processors at all?

Am I misinterpreting the use of the 1747-M13?

Thanks in advance.

As far as I know the memory module is just to store a non-volatile copy of the program.

I dont think the actual program has access to this memory during runtime and as such you are stuck with the amount the CPU originally came with.

So there's no alternative, I have to purchase a 32k processor? I just want to be 100% sure before I go spending the money!

Yes, you have to purchase the bigger CPU to get more useable memory for your program.
The only use of the memory module is to provide backup in case the program is lost.

Another thing to check would be if the program really needs the whole 32k memory. It's not entirely uncommon to upsize the processor for any of a number of reasons (standardization, room to grow, etc.)

If the program is currently under the 16k, you ~may~ be able to downsize the processor. Likewise, if you're a good programmer and the program is just slightly over the 16k, there are often some things that can be done to optimize a program (Not very many programmers spend alot of time on memory optimization...)

One thing to remember is that the data files (B3, N7 etc) take up memory space even if you don't use them in your program. The size of the files are user set, so sometimes they can be trimmed to save memory.

Barry

bazzab1 said:

One thing to remember is that the data files (B3, N7 etc) take up memory space even if you don't use them in your program. The size of the files are user set, so sometimes they can be trimmed to save memory.

Barry

Click to expand...

And of course that the data files are continuous.

N7, N8, N9, ...

I believe that each data file takes up two words just to exist.