I/O problem with S7-315-2DP

Nepiter

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Never come across this kind of problem..

I'm setting up new system, and I/O:s are already been decided.
There is only one 32 bit 24vdc input card, and one 32bit 24vdc output card.
Input area should start from 1 to 4, and output area from 1 to 4 too.
System will be also added 4 inverters, but that's not the problem, those are not even configurated at the moment.

At hardware configuration, input cards default values would be from 0-3, and output card from 4-7.
With this configuration system would maybe work.

But when I change inputs and outputs area to 1-4, for some reason some of bits from output byte 1 are "ON" state, when cpu starts... :unsure:
And I do not have even OB1 yet..

Is there some interrupt or something at 315-2DP, which writes to output byte 1?
If I try to reset these bits from VAT-table, they remains at state "1".
Also first three bits from output byte 2 are not changeable.

Or am I just too tired.. o_O
 
If I understand correctly, the problem is that the output bits do not follow your code ?
If so, check if you have inadvertently adressed the same addresses elsewhere. Check each bit with the "go to address", and be sure to have the "display overlapping address" ticked.
If you have some indirect addressing, then there is also the possibility that something has gone wrong here. It may be harder to find. You can try to search your blocks for STL references to AR1.
 
Nepiter said:
Never come across this kind of problem..

I'm setting up new system, and I/O:s are already been decided.
There is only one 32 bit 24vdc input card, and one 32bit 24vdc output card.
Input area should start from 1 to 4, and output area from 1 to 4 too.
System will be also added 4 inverters, but that's not the problem, those are not even configurated at the moment.

At hardware configuration, input cards default values would be from 0-3, and output card from 4-7.
With this configuration system would maybe work.

But when I change inputs and outputs area to 1-4, for some reason some of bits from output byte 1 are "ON" state, when cpu starts... :unsure:
And I do not have even OB1 yet..

Is there some interrupt or something at 315-2DP, which writes to output byte 1?
If I try to reset these bits from VAT-table, they remains at state "1".
Also first three bits from output byte 2 are not changeable.

Or am I just too tired.. o_O
Click to expand...

First check in monitor/modify if any outputs are on.

Then check if you have some wild voltages on your output terminals / check the wiring. You din't swap the input and output plugs?


Else, please zip and post the configuration.



Kalle

Edit: Perkele, I wrote a lot of rubbish, didn't read your post properly. Sorry.
 
Last edited:
Also, update your program.
Preferably have symbolic address priority selected, then do a block consistency check, and then download all blocks, and check the outputs behaviour again.
 
When you say you have nothing in OB1 then the outputs are not program related.
If you put 24v+ onto the output terminals this turns on the output LED, irrespective of program, so you probably have a connection/wiring issue.
 
He can see that the outputs goes on in monitor/modify.
Either there is a running OB35 joking with him, or he is too tired - as he suggested.

I recommend a quiet rest in the sauna.

Now it's time for soccer EM. I cheer for Sweden this evening!

Kalle
 
I do not have any code yet at plc..so it cant be program related.
Just downloaded hardware configuration to cpu, and after cpu restart, output byte 1 gone wild.

Cpu is somehow controlling those outputs, because I really can see them being state "1" from monitor/modify table.

First I tought wrong wiring also, but monitor/modify tells me that it is something else.
And after cpu startup, 6 bits from output byte are state "1", after 2 second, only 4 bits are on.

This is so weird..
And believe Me or not, but this is not my first cpu configuration.. :ROFLMAO:
 
Something is reserving output double word 0, because at hardware configuration, "system default" output addres is starting from 4, not from 0.
And now I have unchecked "system default" from output card "Addresses" field, and changed address area to start from 1.

I just have no idea, how to solve what is controlling those outputs.. And I cant change address areas anymore.. o_O
 
I've tried to put blank OB1, and tried to change address area to 0-3.
Same result.

Now I have tried to change address area to 4-7.
Then all outputs from that area are at state "0".
But from monitor/modify-table, I can see that those 4 bits from output byte 1 are still at state "1".

I quess I do not have any other solution, except to change my address area to 4-7.. And ask new wiring plans etc.

Alltough, it would be interesting to know, what is setting those bits on..
 
Nepiter.
It does not make sense. Something is wrong. You should try to find out what is wrong.

I suggest, as I wrote before in post #2, see if the outputs are addressed elsewhere.

And also as I wrote in post #4, update the program and download again, so you are sure that the change of the i/o addresses permeate through all the code.

And if that does not reveal anything, then archive and post your program as Kalle suggested in post #3.
 
Yes, I have updated and then downloaded again, no effect.
Outputs are not programmed at all yet.
I do not have any code in plc.
OB1 is just blanc.

PLC, I/O cards and memory card were brand new.
I build up a hardware configuration, and downloaded that in to PLC.
After hardware download, I did notice those outputs on.

I have not programmed any ob's, fb's or fc's, because I found this I/O problem after hardware download.

Only thing what comes in to My mind, is that some internal OB is writing to those outputs. I have tried to look from CPU properties, but I cant find anything related to those outputs.

I'll have a day off tomorrow, so I'll archive hardware day after tomorrow.

Thank You for everyone so far!!
 
Could there maybe be an OB100 or something like that on the memory card in the PLC? If you go online with the PLC is the only block present OB1, the SFBs, and SFCs?
 

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