Siemens S5-95U memory full problem

[Shawn Cassidy]

Hi,
I'm having a problem with a S5-95U PLC. I'm doing some on-line edits to PB0 and when I accept the edits I get a warning "memory in PLC not adequate". I read some previous threads and they refer to compressing the memory. What are the risks. I also checked the memry usage and it is very high. 100 to 3FAD occupied of 40FF. I understand that compressing the memory will free up some of the unused areas. I don't have much experiance with S5 and find the documentation a little confusing. Should I do all edits off-line. Are there any documents that can help with editing S5 programs available? Something simple and straight forward rather than the Siemens documentation...
Thanks

 

[L D[AR2P#0.0]]

The memory may be so full that you will need to delete PB0 in the CPU and then download the new PB0 from the programmer.

 

[curlyandshemp]

Hi,
I'm having a problem with a S5-95U PLC. I'm doing some on-line edits to PB0 and when I accept the edits I get a warning "memory in PLC not adequate". I read some previous threads and they refer to compressing the memory. What are the risks. I also checked the memry usage and it is very high. 100 to 3FAD occupied of 40FF. I understand that compressing the memory will free up some of the unused areas. I don't have much experiance with S5 and find the documentation a little confusing. Should I do all edits off-line. Are there any documents that can help with editing S5 programs available? Something simple and straight forward rather than the Siemens documentation...
Thanks

If you are using Step 5, you may try going to the PC FUNCTIONS screen and select COMPRESS to free up memory.

One cool feature of S5, it keeps a copy of programs during downloads until the download is complete. This ensures that an interrupted download will not corrupt the PLC , something AB does not have

 

[Shawn Cassidy]

That's what I ended up doing. It did free up some space that allowed me to make the changes. Do you know where I could find info concerning how much memry is required for certain functions, contacts, etc. I need to add some monitoring in the program and don't want to run into a lack of memory space.

 

[parky]

The amount of memory will depend on the size of block you are trying to modify online, it needs enough memory spare to load the modified block before deleting the old one.

i.e. if the block you are modifying is 1000 bytes long then you will need at least this plus a bit more, sometimes the only way is to put the processor in stop, delete the block then download the block.

Try looking at the program to see if some slick programming could reduce the total memory i.e. create a function where there is a lot of repeated code, reduce datablock size if blocks have been configured at 255 words & only some are used etc.

 

[Shawn Cassidy]

Thanks for the tip. I'll give that a try.

 

[parky]

Some useful ideas are:

Timers, some people use the block timer this has 3 nop's in, change to stl & remove the nop's, insert a segment end between the setxx & the A txx = xx (in stl the segment end is bld255.
This then when displayed in ladder shows timer as an output coil.
eg:
a f0.0
l kt5.2
sd t1
nop0 (remove these & enter BLD255)
nop0
nop0
a t 1
= f0.1
will display timer in LAD but the timer output will be on another rung
this will save 2 instructions for each timer however this is not possible if words are assigned to the unused functions on the timer.
also like the one I had to mod with no memory, I created a function for the 30 conveyors, passed the i/o to the function & this saved me a few hundred instructions.
Note: it's some time since I have used S5, but I think bld255 is segment end. (after typing in bld255 it reverts to *** which is segment end.