s7 help

[lesliemcg]

Hi guys
new project requires S7-300 plc
have got a 313-2DP and am having problems with FC blocks.
simple logic isnt working like there is a conflict or something. no errors are shown in simatic manager
but a coil isnt latched when its supposed to????
in say motor start stop circuit. I find its works ok and when I build up the logic it sort of jams for some reason
background is from GE Fanuc so i'm am working from previous experience just a new to siemens (feel like going back to GE though)
can anyone help please
thanks in advance
lesliemg

 

[PLucas]

Lesliemcg

Could you explain your problem a little bit more clearly, from what you have stated I do not fully understand what problem you have got.

I will try and make a bit of sense from your post.

You have written some simple logic in a FC block (say FC1) and this works OK, then when you add more logic the block does not function the way you expect, is that correct?

You mentioned a coil isn't latching when it is supposed to, is this a set coil (S) or just an output coil (or flag).
If it is the later, have you addressed this coil only once or have you fallen into the trap of 'double coil' syndrome?

A copy of your logic would help here and a bit more information.

Paul

There are 10 types of people in this world.....
Those that understand binary and those that don't!

 

[lesliemcg]

no problem paul, it does look like a double coil error so I tried using the same logic with internal flags (m0.0 etc)instead of #temp ones
I am not using set/rest on the outputs/flags just a simple latch circuit.
your right, it circuit worked until I expanded it with more logic only to get problems
I will send you a copy of the program to give you a laugh of where I'm going wrong
how do I attach the zip file to this forum?
I am also using simatic 5.2
cheers
lesliemg

 

[PLucas]

Lesliemcg

Does that mean you have now solved your problem or do you require more help?

I will be honest with you now, I have not got a clue how to attach a file in this forum, I only occasionally pop by here to see what's going on, so I am not fully up to speed with the ins and outs of this forum yet.

I can always be found at PLCs.net forum, there is a link to that site in the links tab of this forum. You can attach files to the posts there. My logon at that site is also plucas, or you can send me an email from there.



Paul

There are 10 types of people in this world.....
Those that understand binary and those that don't!

 

[jacekd]

Hi,
variable defined as temp is deleted from memory after fc is finished, so it won't work as Set/Reset.

Regards,

Jacek

Do it right or don't do it at all.

 

[lesliemcg]

Thanks for the help guys

I now have the program working
the problem was in the temp tags # not latching due to memory (thanks jacekd) and when I used the M0.0 tags instead I didnt realise they shared the same address as MW0
S7 is so diffrent from VERSAPRO (GE-FANUC)
so thanks for your help again

lesliemcg