M251 crash with error

[lukbok]

Hello Guys

I have TM251MESE on table

This PLC has 2 ethernets:

a. to ethernet 1 is connected modbus tcp device

b. to ethernet 2 is connected weintek hmi and laptop

When i plug in and plug out rj45 plug on ethernet 2 PLC goes stop and error (I/O led shines, ERR led is flashing very fast)

The communication between laptop and PLC is terminated.

When i reconnected laptop to PLC i see that PLC is empty and i have to download application again and start PLC

PLC works to next plug in and plug out rj45 on ethernet 2.

Can you help me?

In attachment i am sending files from PLC just after crash.

PLC firmware: V5.0.8.7

Machine expert 1.2.10

best regards

Lukasz

[gbisheimer]

I have the exact same problem but with a TM241. The PLC goes to STOP but I can still connect to it using SoMachine and also the WebPage. The WebPage shows that there is no application loaded on the PLC and the same is informed when I connect using SoMachine.

If I power cycle the PLC, then it starts normally. The program and data is still loaded in the PLC as nothing happened.

At first I thought it may be a problem with the old firmware, but then I found this post using a newer firmware reporting the same problem, so it's seems it's not fixed yet.

I'm using:

Firmware v4.0.6.26

SoMachine 4.3

Do you have any ideas on how to fix this problem?

Thanks.

[SteveAndjic]

Hi Lukasz

Let's first look at the beginning so we can get a better understanding

On ethernet 1 you have a modbus TCP slave device connected..

On ethernet 2 you have your HMI plus you are connecting your laptop..

Unless you have changed your configuration, ethernet 2 is always configured as the device network so in theory your modbus TCP usually would connect to this network

Ethernet 1 you would usually have your factory LAN or internet connection and HMI/SCADA 

I myself have experienced issues on the M251 when connected to the ethernet 2 device network. If you are viewing it's usually ok but when making changes or downloading that's when the issues begin

the CPU on the M251 has 2 cores, 1 for the OS and Application and the second to run the comms. The issue that you can experience when connected to the ethernet 2 network is that while connected it also activates the non volatile memory in the PLC. Any changes made will also sit in the non volatile memory as well until you update the boot application file. 

Sometimes when you disconnect from ethernet 2 the non volatile memory stays open and the OS and application will detect a mismatch and go into stop mode even if you have not changed anything as you have connected to comm core instead of the OS application core and it doesn't update. It will then do a memory dump, which at times can cause the application to delete but most times its still there and will work after a reboot unless you made a change and didn't update the boot application file then it will always boot up into stop mode. You can always just update the application or re-download it

This is a possible cause that I have experienced but might be the actual cause.

Just stating my 2 cents for now hoping that it might help a little

[lukbok]

Dear Steve, Gbisheimer

thank you for your help and tips.

Steve, perhpas you are right but how to solve the problem? Moreover - how to avoid this reaction?

This is unacceptable that when we disconnect ethernet 2 plc goes error

What do you think?

In attachment i am sending my configuration

best regards

Lukasz

[SteveAndjic]

HI Lukasz

Maybe try and see if the same thing happens when connected to ethernet 1. 

Regards

Steve