Cpu 318-2 dp issue

Dear all,

I encounter a problem on a siemens 318-2 DP, old model, with a backup memory-battery and a memory card (no MMC)

This plc is connected via profibus cable to a SIMATIC MP270B touch-10 TFT multipanel display.

Everything was working until day before yesterday. Since yesterday, the values ​​displayed on the screen "with sensors ..." are filled with #### ..

When using touch screen "MP270", there are error messages: PLC ADDRESS ERROR ..

Only the LEDs "5VDC and RUN" are lit (so in normal mode), and the backup memory battery has a correct voltage of 3.5VDC.

I checked, while checking the continuity of this cable profibus ", no problem..moreover, by disconnecting this cable since the plc, the multipannel always displays the same ####

I changed the multipanel with a new and already programmed, same #####

My questions :

1) Can this still be an "internal" problem in the CPU? and if so, why is the SF LED not lit?
2) Do you think this is the erased memory? and if so, why the led "BATF" is not lit?


Do you have a troubleshooting methodology without the S7? can be input / output modules ?

Many thanks for your help

Bruno

Sorry, i did forget to add, that i switched from run to stop and power off the plc, so far without any success..

Bruno

The only troubleshooting you can do without STEP 7 software is to check if any outputs are ON that are supposed to be ON when you power up the PLC, or to attempt to start the machine without using the HMI if hard-wired buttons exist for machine control. Otherwise, you need STEP 7 software to properly troubleshoot.

You can download a trial version here:

https://support.industry.siemens.co...elease-for-simatic-step-7-v5-6?dti=0&lc=en-WW

You will need at least a PC Adapter USB to connect to the S7 PLC as well:

https://mall.industry.siemens.com/mall/en/WW/Catalog/Products/10204161?activeTab=product

Many thanks for your reply.

Yes, all outputs are ON, same as before except 1.

This CPU is used on a crane , so the soft is protected... i dont know if with step 7, it's always permitted to troubleshoot ?!!

Any idea about PLC ACCESS ERROR messages ?

Thanking you

bruno

I have seen failed MPI or Profibus ports on CPUs. This could be the problem... But the only way to be sure is to try to connect with STEP 7 or replace the CPU with an exact replacement, and hope the memory card has the complete and current program on it .

do you know, what could be the damage to profibus port to cpu, overnight?

So you confirm that with STEP 7, I can do troubleshooting, even if this program is protected by the crane maker?

many thanks

bruno

I can't say for sure in your case what it was... power surge, age of the CPU...

If your CPU is password protected, that means if you get a good connection with STEP 7, you will be prompted for a password. If the connection is bad, you will get an communication error message.

That is the extent to which you can troubleshoot, just the connection to the CPU from the computer. You will need the password from the manufacturer to troubleshoot the program if your CPU is password protected.

PS: it could be the cable or the connectors that have a problem.

Thank you for reply...

indeed the CPU is passeword protected, which is normal and i agree...

my concern is to test what is possible, with my means, to avoid moving the manufacturer that will prove a very expensive operation.

Because this same operation, a few months ago, we were charged for 15000usd, only the PLC (318-2 DP was replaced by 319-2 with mmc card) and we had add a soft engineer and tests (at 1500USD / day during 10 days) ...

It is not possible to get the source program or the passeword plc.

the profibus cable, I checked the connections and continuity (red and green wires that are well connected between terminals 3 and 8 ...

please advise how can I test the cpu profibus port ?

If this profibus port is damaged, should the SF be lit ?

Should be one of the input module, beacause high current/tension, the root cause ?

Many thanks

BRUNO

The first thing I would do is rewire the Profibus connectors. If that doesn't work, replace one, if that doesn't work replace the other one. I've had bad profibus connectors, even with continuity along the cable.

Many thans sigmadelta,

I have reolaced both end profibus connectors but the situation is same as before....

Could be the CPU profibus port itself ?

Bruno

It's possible yes. I've seen it happen before.

The only true way to test is to get a PC Adapter USB, and try to get online with the trial version of STEP 7. If you get a password prompt, your port is OK, if not, you will get an error.

The last resort is to do an overall reset of the CPU with the Memory Card in the CPU. Maybe the contents of the internal RAM were disturbed and needs a reload from the memory card. Have you done this overall reset before?

Dear sigmadelta,

in waiting to get the profibus cable from the supplier, could you please advise the way to do "theoverall reset of the CPU with the Memory Card in the CPU" ?

Many thanks

Bruno

Sure, but read the whole procedure through a couple times before attempting. Again this is a last thing to do, when other attempts have failed, before having to call your crane guy to come in. If this doesn't fix your issue, you may just end up calling him in anyway.

There are 4 positions on the rotary switch on the front of the CPU:

RUN-P
RUN
STOP
MRES

The switch does not stay in MRES, it springs back to STOP when you take your hand off.

First, do whatever you normally do to stop and park your crane (put it to home, for example), if possible.

1) Switch the CPU to STOP
2) Hold the switch in the MRES position for about 3 seconds. During this time the STOP will flash slowly.
3) after this 3 seconds, the STOP LED will stop flashing
4) release the switch and quickly switch to MRES and release quickly
5) The reset is successful if the STOP LED blinks rapidly for about 3 seconds. If not, try again.