Upgrade CPU from 240 to 250-1

[Chris Elston 79]

Newbie here... I developed a program with a 240 CPU. (DL205). I'd like to upgrade it to a 250-1 CPU. Is there anything special I have to do to my program to tell my ladder program that I have a different CPU? I've looked around in the software and can't find anything. I don't have my CPU yet, but was trying to do some homework. It almost looks like you just drop it in and the ladder knows, the software knows. So then I assume that the RLL instructions in Direct Soft will automatically enable. For example, all the floating point instructions, and Bit for Word instructions that I am seeking in the 250 that i don't have in the 240. Any words of wisdom?

[b_carlton 61]

To actually do the change in the software just go to PLC-Offline Setup and choose the new CPU. The 250-1 doesn't have the little pots that are on the front of the 240. The 250 also doesn't have the 'non-volitile memory' feature (this is a memory area that, if stored to using a MOV command, is stored in the EEPPROM itself and is reloaded on power up). Otherwise the system V memory and SP relays seem to be the same. The 'bit of word' commands are very powerful. Too bad they don't have an instruction where the bit can easily be selected at run time. I've had to use bit masking for that.

[Chris Elston 79]

Thanks B Carlton. Yeah I have an analog card in of the machines and need to do some floating point math. I didn't realize that the 240 didn't support it until I was trying to program it. Live and learn...I think for $60 more from a 240 to a 250, I think I'll always try and get a 250 no matter what.

[b_carlton 61]

And if you ever have to do Modbus communication get the 260. The MRX, MWX commands make that incredibly easy.

[Chris Elston 79]

Sounds like excellent advice! Thanks again. So far doing ok with Automation Direct. I think the 250 is the way to go. I feel so "held" back or "jarred up" using this 240...feel like I can't do anything I want to do "fancy"....