problems with floating point files and math operations rslogix 500

[iarriagadap]

Hello everybody
I'm new to plc programming and i'm trying to program some simple math operations to convert some measurments for a project. The problem is that when i try to use floating point variables in the intstructions (particularly, in the SUB instruction), after compiling, i get this message

rung 4 ins 0: ERROR: Program could not be compiled!Instruction not valid for processor.

Im currently using a SLC 5/03 1747-L532B with OS301, and the Instruction set guide states that floating point (F) is a valid file type with the sub and add (and mos of the others) instructions.

anyone has had the same problem?

 

[rdrast]

Post the exact logic (instruction) you are trying.

Some instructions do not work with Floating point, though virtually all math instructions should.

Is the floating point file big enough to cover the address you are trying to reach? It defaults to one element after all.

 

[iarriagadap]

the exact instruction is


-SUB---------------
Substract
Source A F8:0
0.0

Source B 1.6
1.6

Dest F8:1
Source A 0.0
-------------------

it's the only instruction in that line. And that's the line with the problem

 

[fuzzy logic]

Very strange.... try to delete this instruction, recompile, save and then add again your SUB.

Which version of software are you using?

- [font=comic sans ms,sans-serif]fuzzy logic[/font]

 

[bernie_carlton]

That "SOURCE A" at the end of the instruction is suspect (though it may be just a typo). My RSLogix500 compiled that instruction ok for the PLC type and OS you specified.

 

[iarriagadap]

yes it is. i tried creating another project, same processor, and it compiles. i don't know what could be the problem really

 

[LJBMatt]

Can you post a screen shot of the instruction. A picture is worth a thousand word.

 

[Mickey]

Can you post the actual .rss file (zip then post) for the processor in question. A resent upload. Are you sure its a OS301 and not a OS300?

 

[iarriagadap]

yes, it's OS301.
But i solved the problem!
I just created a new project, copied everything from the original, and it compiled!, no errors. I really don't understand what could have happened with the original file of the project.
Thanks everybody