I never have done such a thing, but I think it should be possible, but this would imply unifying the two networks...

Normally and preferable each PLC has its own Profibus network. And if I/O communication is needed, a DP/DP coupler is the way to go. Do some research and try to understand the benefits of the DP/DP coupler, if you believe they can be bypassed, then you could put them together.

Hopefully your PLCs have a small number of slaves, since you have to rearrange all all Profibus node address.

Or just have both Profibus plugs in the VFD cabinet, switching manually them...

Now you have to do some code work to select whom will be the Master and deselecting the other PLC. You can use the Deactivating and Activating DP Slaves/PROFINET IO Devices with SFC 12 "D_ACT_DP.

Deactivating a node will prevent the CPU reporting errors due a missing slave. This function is very useful for example when a robot changes the tooling.

This are just some thoughts I hope helps.

I see what you are saying, I guess the best option for you would be keeping they separated, and then easy-breeze.

I could find that in a multiple master system that is possible to share devices however to read the inputs, butI am not sure about outputs. Perhaps someone else could help us here...

 Hi

I am dealing with the same problem in my project. could you please share the results.

Thanks

Georgio

Profibus in general is multimaster system. But only one master is able to communicate with appropriate slave. I think two masters cannot communicate with one slave (only some slaves have the posibbility to communicate with several mastesr - but only via inputs to masters).

But I think it should be possible to add one slave to two hardware configuration to profibus network (the same profibus address on each network). Than connect profibus connection (two PLC and slave). Than in one PLC deactivate slave, on the second PLC activate it. If I want to I can switch activation/deactivation - I will try this solution, it should work. I will test it also with Profibus analyser and test profibus packets on profibus networks..

Thank you.

Georgio.

mtb4outdoor

 Hi

I am dealing with the same problem in my project. could you please share the results.

Thanks

Georgio

Profibus in general is multimaster system. But only one master is able to communicate with appropriate slave. I think two masters cannot communicate with one slave (only some slaves have the posibbility to communicate with several mastesr - but only via inputs to masters).

But I think it should be possible to add one slave to two hardware configuration to profibus network (the same profibus address on each network). Than connect profibus connection (two PLC and slave). Than in one PLC deactivate slave, on the second PLC activate it. If I want to I can switch activation/deactivation - I will try this solution, it should work. I will test it also with Profibus analyser and test profibus packets on profibus networks..

Thank you.

Georgio.

 

 Hello,

have you already seen this:

Reading the input data of a DP slave configured by a different DP master

or you can take some data from slave by DP/DP Coupler 

http://support.automation.siemens.com/WW/view/en/1179382

Hello mtb4outdoor;

As you have seen with the answers provided in the thread, Profibus-DP standards do not support master redundancy; if this is what your client would like you to implement, the following link could provide a solution:

https://www.kunbus.com/profibus-redundancy-switch.html

We studied this redundancy switch a few years ago, when it was still known as a Comsoft PRS relay, for a project that required shared control of a Profibus network by two masters from different manufacturers. The tests we did were very satisfactory; unfortunately the client ended up choosing a different solution in our project. All in all it was a satisfying solution that provided an alternative for the loss of a Profibus master and the switch to another in case of failure, seamlessly.

Note that the redundancy switch only supports DPV0 slaves.

Hope this helps,

Daniel Chartier

I have the same request from a customer, but the request relates to a PROFINET node, not profibus.

Can I use the same solution?

With profibus, I solved in the past the issue by using 2 repeater and powering them on alternatively

Hello Alberto;

A Profinet IO device can be defined (and used) as a shared device exchanging its (shared) input and output areas with 2 IO-controllers.

Ses this document: 

How, in STEP 7 (TIA Portal), do you configure access to a shared device and the function Module-internal Shared Input / Shared Output (MSI /MSO)? 

https://support.industry.siemens.com/cs/ww/en/view/109736536

Hope this helps,

Daniel Chartier