Hi all!

I have this problem, where F-DI 8x24VDC HF [6ES7 136-6BA00-0CA0] module gives overtemperature failure. It stops the machine and as in manual, it needs to power off and back on to remove the fault.

Fault can come active randomly, it can fail 5 times in hour, or it can work whole day whitout nothing. 

The F-DI module is in rack of ET200SP and CPU is CPU315F-2PN/DP 6ES7 315-2FJ14-0AB0.

System has also HMI-pane and all of the units are connected with profinet.

What I have done at this point:
- Measured temperature of module, and it is near 50 Celsius. And in manual says that max. usage       temp. is 60 Celsius
- Chanced F-DI module card to new one.
- Chanced baseunit of F-DI module.
- Changed position of F-DI module in rack.
- Changed different CPU
- Changed different ET200SP module
- Added extra cooling to panel

What could cause this fault?

- Juha

Hi Hati!

There actually was inadequate cooling and what i forgot to tell, I added yesterday extra cooling to panel.

I modify it to my starting post.

- Juha

Hey mopS04!

Thanks for your reply.

The installation seems to be done right.

I have this extra cooling made by dry air with low pressure from distance to blowing to module. 
It seems that it doesn't help if I try cool hole cabinet with that. So I pointed air source more near that rack. 

Lets see if that helps for it.

I assume from these answers, that temperature measuring is usually working in these kind of failures?

- Juha 

Update;

At the moment, there is extra cooling and there has been changed all the parts of the rack and that same failure gets active when ever it pleases.

Next thing is to install extra groundings to din- rail of rack.

And after that it is meaning to change systems power supply.

Will see, if those will help.

-Juha

Hi dani.lara,

It seems, that extra groundings helped in our case.

We grounded the DIN-rail of the ET-module with extra connection and installed extra copper to machine with the problem.

Another change in same time was the power supply, but I'm not sure if it was that what helped in our case.

The problem is not completely solved, because it has done the failure two times after fixings, but failure activity was like 70 times in shift before. That's why I personally think that the problem was in groundings.

I have ordered also varistors, because machine has relay controlled magnetic valves. There have been some problems with relay contacts.

But that doesn't have anything to do with heat problem in our case. The temperatures were in 40 Celsius in our case.

We are having a similar problem with F-DQ 4x24VDC/2A PM HF modules and contacted Siemens about it. Below is the response from Siemens:

"Details from the factory suggest that the two variations of the ‘over temperature’ fault are either as the name implies, or an external noise source which is monitored via the firmware. To expand on this slightly, the factory offered the below details on how this is monitored:

Over temperature is detected both with the µC and the inverse-polarity protection. Whereas the µC monitors the module temperature in general, the inverse-polarity protection monitors the voltage before and after itself. If the difference is to high (Δ0.8V), then it protects itself for overheating and the module passivates. The module is passivating to avoid any damage, also

Based on this, this means that we need to isolate any noise source greater than 0.8V and to date, typically greater than 45kHz. No other known noise sources are on record as issues for generating heat within these modules. Examples of such frequencies are from VSDs or PWM outputs. Both of which I believe are not in use on site, or at least in close proximity to the PSS equipment.

With regard to separating or isolating the two alarms, there is no other diagnostics we can offer at this time.

There is a next gen version of the card planned which will see the alarms separated, however this requires new hardware and not able to be flashed into existing hardware.

If we are looking at a true thermal issue, the internal electronics is designed to operate to 85’C. Hence the thermal images captured are well within specification at time of capture. Note also that the ET200SP failsafe modules must include temperature monitoring as part of the failsafe certification. This means that the modules must passivate outside of a defined range."

We managed to reproduce the fault by introducing 10kHz ~ 60kHz noise on module power supply in our test setup, but were unable to detect any noise on the filed.

Did you manage to fix the issue permanently?

Hi Emtabar,

Yes, problem seems to be solved by the groundings we did.

As the answer from Siemens looks like at quick reading, and if there is some kind of noise in wrong place in wrong time, module will secure it self from the source. 

Juha