Siemens CPU 315-2DP Troubleshooting

[Mullet]

You can try for test. Take IM151-3 module from other non working cabinet to first cabinet Connect profibus cable and power to this other IM151-3 module (don't forget end resistor of IM151-3) Dont't change any slave dips and don't connect any IO-cards to IM-module.
If CPU detects this other IM151 module, but says faulty (as there is no configured IO cards connected) then problem is on cabling (or in first cabinets profibus connector outlet) after first working cabinet.
If it still says that for IM151-3 no available then there is other error.

Just wanted to respond back to this. We did this and it helped us narrow the problem down and eventually fix it. Thank you very much!

It's funny because I do things like this to troubleshoot all the time, but I think getting used to new software and protocols and processes threw me off my usual track.

So the electrician had replaced the Profibus cable between 1 and 2 and had replaced the connector at 2. What we found was yes, the IN side of 1 worked, but the OUT side did not. They didn't have any more connectors on-site so what we ended up doing was swapping connectors with 1 and 6, since 6 was the end of the line and didn't need an out.

We got everything coming in and talking!

Thanks a ton for everybody's advice on this! I really appreciate it.

 

[Ken Moore]

Almost every Profibus problem I have ever encountered, was the cabling and terminations. 1.5 megabaud is kind of the default for most industrial sites. I have been to some where they slowed everything down to 9600, just to get things working. Siemens used to sell a handheld tester, was expensive as most Siemens stuff is, but now they have been discontinued, and are several thousand dollars.

 

[AlfredoQuintero]

You can buy Profbus connectors in eBay at a very low cost. It is a good idea to keep some spares in the warehouse.
Great you were able to fix your problem.

 

[Mullet]

You can buy Profbus connectors in eBay at a very low cost. It is a good idea to keep some spares in the warehouse.
Great you were able to fix your problem.

Yeah we saw that. We got some ordered in case it comes up again.

Almost every Profibus problem I have ever encountered, was the cabling and terminations. 1.5 megabaud is kind of the default for most industrial sites. I have been to some where they slowed everything down to 9600, just to get things working. Siemens used to sell a handheld tester, was expensive as most Siemens stuff is, but now they have been discontinued, and are several thousand dollars.

Yikes. Yeah according to the guys at the plant the system has worked with minimal issues for 15 years or so. Seems fairly solid. Sounds like a power module went bad which fried some stuff and caused all this.

I didn't realize you need a special USB connector to get into the PLC directly. Luckily they had some kind of modem module next to it that I was able to get into with a USB printer cable. Siemens quoted us on their special USB cable and it's $740. No thanks.

Also their software licensing costs seem to be pretty ridiculous. I thought Rockwell was the worst but looks like Siemens isn't too far behind.

 

[Lare]

Thanks of informing that troubleshoot worked.
Was profibus connectors older screw terminal type or newer knife type?

Sound like that you mean MPI/Profibus RS485 programming adapter with USB connector.

 

[Mullet]

Thanks of informing that troubleshoot worked.
Was profibus connectors older screw terminal type or newer knife type?

Sound like that you mean MPI/Profibus RS485 programming adapter with USB connector.

They were the knife type.

Yeah that's correct, their RS485-USB programming adapter.

 

[Rob...]

Siemens 6GK1571-0BA00-0AA0 PLC S7 USB to MPI ProfiBus DP PPI 32 64 bit

PLC Cables, PLC Trainers and Industrial Automation Supplies

www.plccable.com

I've used this successfully, and a lot cheaper than the official Siemens A2 adapter.

 

[JRW]

Siemens 6GK1571-0BA00-0AA0 PLC S7 USB to MPI ProfiBus DP PPI 32 64 bit

PLC Cables, PLC Trainers and Industrial Automation Supplies

www.plccable.com

I've used this successfully, and a lot cheaper than the official Siemens A2 adapter.

Unless you have a profibus network above 1.5 meg…

 

[Rob...]

I never noticed that caviat. Never tried it.

I carry a Siemens A2 anyway, but for the OPs need it would work fine.

 

[Mullet]

I never noticed that caviat. Never tried it.

I carry a Siemens A2 anyway, but for the OPs need it would work fine.

That's great actually. We'll probably try to pick one of those up in case we have to go back there. Definitely beats paying the $740

 

[AlfredoQuintero]

I didn't realize you need a special USB connector to get into the PLC directly. Luckily they had some kind of modem module next to it that I was able to get into with a USB printer cable. Siemens quoted us on their special USB cable and it's $740. No thanks.

Also their software licensing costs seem to be pretty ridiculous. I thought Rockwell was the worst but looks like Siemens isn't too far behind.

I think for the old Simatic Step 7 (as well as the new TIA Portal) Siemens allows the download of an installation that works for 20 or 21 days.
Also, there are alternatives (non-Siemens) third-party USB to MPI adapters. One of this forum's members has an online store which offers this hardware for a more reasonable pricing.

Edit: Form this member...

geniusintraining​

www.PLCCable.com

 

[Lare]

That's great actually. We'll probably try to pick one of those up in case we have to go back there. Definitely beats paying the $740

What was exact product code?
Siemens have couple different and price is different.

 

[AlfredoQuintero]

What was exact product code?
Siemens have couple different and price is different.

https://www.plccable.com/siemens-plc/

 

[Lare]

https://www.plccable.com/siemens-plc/

I meaned original quoted Siemens cable as price was years ago lot cheaper.

 

[Ken Moore]

In the USA, $740 is cheaper than the serial module was.