help with s7-200 faultfinding - how is M0.0 set?

hey

i've been working on a machine that is not operating correctly, and i am having trouble interpreting the PLC program

the machine seems to be timing out in between steps and faulting

unfortunately i do not have the original program file, hence i have no comments or symbol information

from what i have been able to work out so far, M4.0 needs to be set when a certain part of the machine passes over a sensor, but M0.0 seems to be breaking the rung conditions that set M4.0 before this happens

the problem is that i can't see anywhere that bit M0.0 is set in the program, only where it is reset

i have attached the program file (step7 microwin)

the logic of interest is in networks 2 and 3 in the AUTO block

how is M0.0 being set?

I can have a look tomorrow if you want - it's 10pm in England and I am at home without my laptop!

markie said:

I can have a look tomorrow if you want - it's 10pm in England and I am at home without my laptop!

Click to expand...

that would be great, thank you!

Post it as a PDF as well more folks can have a look that way (not everyone will have microwin)

Have you searched for M0.0 ?

It could be being set by a HMI ?

Does MicroWin support source code ?

504bloke said:

Post it as a PDF as well more folks can have a look that way (not everyone will have microwin)

Have you searched for M0.0 ?

It could be being set by a HMI ?

Click to expand...

Good thinking - also, could the sensor be operating too late - so the fault is being set?

If it WAS working, it's not likely to be the program, in fact last week I had a failing dc power supply on an S7 200 (Lumpy dc)which was causing sensors to switch off faster than the screen could display.

504bloke said:

Post it as a PDF as well more folks can have a look that way (not everyone will have microwin)

Have you searched for M0.0 ?

It could be being set by a HMI ?

Click to expand...

i've attached a PDF file of the ladder logic

page 27 is where to look at

i have done a cross-reference report in microwin and it does not show M0.0 being set anywhere

an OP3 HMI is being used to start the machine cycle by pressing the F1 button. could it be possible that this is set up as a toggle button that sets M0.0?

i didn't think of this..

i was more worried that M0.0 was a bit that was set by some sort of system function like i have seen in some s7-300/400s

i agree that it is not likely that the program is at fault, in fact i think it may be a VSD playing up and not operating as quickly as it should be. i just wanted to understand the logic first

L D[AR2 said:

Does MicroWin support source code ?

Click to expand...

i'm not sure, i am fairly new to microwin and siemens in general

The fact that the bit M0.0 is being reset on page 28 Network 3 Auto SBR3 then this suggests its being set somewhere, i cant see it in the program so its more than likely the HMI (although the red wines kicking in now and its late!)

Post the HMI program

unfortunately i don't have the software to program the OP3 HMIs... i think it is protool? i have wincc flex, but not this

i think that when hitting the AUTO START button on the HMI, it must be setting M0.0

then there must be something that resets it before the machine reaches the next step in the cycle

i will have to go back out and have a look at it again today

thanks for your help so far

Hi Brendan,

I couldn't open your prog as I have an older version of microwin. I think its likely to be the op unit that sets M0.0.
There are several rungs which will reset M0.0. Perhaps you can use the electrical drawings to get your I/O and build your cross reference and this might help. Not knowing the machine I cant be sure but am fairly confident it's likely to be a sensor.
Does the display list any faults?
Lastly, I know Meldung is German for message but thats not much help!!!

Mark

markie said:

Hi Brendan,

I couldn't open your prog as I have an older version of microwin. I think its likely to be the op unit that sets M0.0.
There are several rungs which will reset M0.0. Perhaps you can use the electrical drawings to get your I/O and build your cross reference and this might help. Not knowing the machine I cant be sure but am fairly confident it's likely to be a sensor.
Does the display list any faults?
Lastly, I know Meldung is German for message but thats not much help!!!

Mark

Click to expand...

You know the service packs for microwin are a free download (last time i looked!) ?

thanks for all your help

in the end i solved the problem

it was operator error.. incorrect setting for some length measurements causing the machine to fault at a certain stage

it was the HMI 'AUTO START' button that was setting M0.0

i couldn't see what was resetting it in the end, but i had wasted enough time on the machine i was just happy to see it going

funny how none of the operators will admit to messing around with the settings

would have saved everyone a lot of greif