Hi, I have inserted in the configuration  IM155-6PN Standard and another technology module Count 24Vx1 in TIA Portal V13.

I can't set it to be isochronous mode, even in the manual say that IM155-6PN ST supports it.

Then I have inserted IM155-6PN HF and it is possible to enable isochronous.

Now, is this isochronous mode on IM155-6PN ST supported or not?

Hello,

no the ST module doesn't support isochronous mode, only IRT, not more.

Regards

Christoph

Doesn't the IRT mean Isochronous Real Time?

unknown user

While RT offers high determinism and precise production, IRT takes it determinism a bit further, providing even more advanced solution. For comparison, IRT can bring cycle times down to less than 1 millisecond. [3] This makes PROFINET IRT ideal for applications where motion control is critical to production cycles, such as a printing press. 

 I am a little bit confused now, what is this IRT then?

Hello,

yes this is the meaning of IRT but it means not thast the device support isochronous Mode.

It means that this device can handle the IRT Protocols and can be integrated in a IRT Topology , not more.

Regards

Christoph

Makes sense now. But this is an ugly discovery, What if I use a HF interface module and I have somewhere in the network also a module that doesn't support IRT, it will hang all the PROFINET network?

I have two Lenze drives with Profinet E94AYCER modules, for now Is still don't know if they are capable of forwarding IRT telegrams. What problems can occur if I want to use isochrone mode on one decentralised IO station?

Hello,

this depend on which position in the topology the non-IRT device is plugged.

The ET200SP ST can connected at any position in the IRT Topology because they have IRT support.

Devices without IRT can only be pluged at the end of the topology or on another PN Port of the PLC like the IRT Devices.

Regards

Christoph

OK, then I can split the bus topology in two legs at the CPU position. The right leg is reserved for devices that can manage the IRT messages, while on the left there are the devices non-IRT capable.

Is there any document on how the Profinet network should be properly wired. I mean, do I have to follow some rule when interconnecting devices from P1 to P2 or it doesn't care.

In the attachment you'll see the HW conf.

 Hello MArko Bursic

can buddy i get the reference from did you copy this text. i have tried to find out but i didn't get it on internet.

thank you
AJEY

Marko Bursic

Doesn't the IRT mean Isochronous Real Time?

unknown user

While RT offers high determinism and precise production, IRT takes it determinism a bit further, providing even more advanced solution. For comparison, IRT can bring cycle times down to less than 1 millisecond. [3] This makes PROFINET IRT ideal for applications where motion control is critical to production cycles, such as a printing press. 

 I am a little bit confused now, what is this IRT then?