Siemens - Device discovery problem

[GazzaSpace]

Ciao guys,

I'm not used to program on Siemens PLCs, but sometimes I have to.
I'm experiencing a strange problem when I try to connect to a PLC.

I'm working on a 2021 MacBook Pro (M1 chip), running Parallels Desktop and a Win11 based VM.
I'm trying to connect via ethernet cable (I do have a USB-C/Eth adapter connected to my Mac) and on my VM I have the network set up to connect to the PLC (S7-1500).

When I try to ping the CPU, I don't see any kind of problem, but when I run the devices discovery operations, it tells me it could not find any node.

Any suggestions?
Thanks

 

[JesperMP]

I dont know Parallels, but I have some experience with VMs.

When you use the 'accessible nodes' TIA scans the network at ISO protocol level, not TCP/IP. This may or may not be possible from your VM. In my PC with VMware I have to setup the virtual network adapter with the real MAC address of the PC.
Since you use a USB-to-Ethernet adapter, does this get assigned to the VM, and not the host ? It should not be necessary to setup a virtual ethernet card in that case. It is easier to use an USB-to-Ethernet adapter than an integral ethernet card in the host PC.
Maybe someone with experience with Parallels can provide further advice.

If you just need to go online from TIA to a PLC that has already been loaded with a hardware configuration, select to go online with 'device with the same address'. This uses TCP/IP and should work if you can ping the PLC.

 

[GazzaSpace]

Hello Jesper, thanks for your answer.

When I connect the adapter to the USB port, the OS asks me if I want to connect it to the real machine or to the VM.
I tried both ways and the difference is that if I choose to connect the adapter straight to the VM, I can see one more network (that has my adapter as source). I tried to use this setup (changing the Siemens communication configuration in Win control panel) but nothing changed.

I knew about the protocol difference between scanning and actually communicating; what are the odds that my adapter is the problem here?

 

[JesperMP]

Let the USB adapter be connected to the VM.

Did you try this ?:

If you just need to go online from TIA to a PLC that has already been loaded with a hardware configuration, select to go online with 'device with the same address'.

 

[BryanG]

If you can ping the PLC then you know that there is a connection, so make sure that is working first. Then it comes down to using 'device with the same address' as JesperMP suggested. I have used TIA in VMs and over VPNs using the built-in Ethernet port on my Windows laptop. I do sometimes have to play with the Ethernet settings, mostly using NAT, and other times Bridged connections, though that may be down to my lack of patience waiting for a connection.

Your big problem, and one you can only blame yourself for, is trying to use a MacBook. I have customers that use MACs and I am forever telling them it would be much easier if they got a proper computer

 

[GazzaSpace]

I've been using MacBooks (this is not my first one) to program PLCs since 2014, never had a problem with Rockwell AB.

I'll try what Jasper suggested, even if the problem that I have now is with a virgin brand new PLC.

If needed, I'm running TIA Portal V16 - Upd4.

Thanks for the advices, I'll wait for someone who uses Parallels


P.S. I know of a colleague who had a similar problem (on a Windows laptop, VMWare VM) when he tried to connect to a Siemens PLC via a wi-fi access point connected with an Ethernet cable to the PLC, so maybe Siemens' TIA Portal is the problem and not the MacBook

 

[JesperMP]

You can set the network details (IP, Subnet, Gateway) of the CPU via the integrated display.
That should be enough to get online even if the CPU is new out of the box.
It seems you have got this far since you can ping it.

When you go online with a router or via VPN, only pure TCP/IP is let through. So 'accessible nodes' might not work.

 

[504bloke]

Thanks for the advices, I'll wait for someone who uses Parallels

I run a Mac with parallels for all my VMs for software on windows

You need to have the Network Adapter connected to the VM under windows (same for USB /Serial etc adapters) and not done through the host (Mac) on a bridge etc

You need to have the windows IP for the Network adapter set up correctly (ie not dhcp set to manual etc)

Now this is weird to siemens and it doesnt happen often and I still havent got to the bottom of it - sometimes my TIA cannot see things on the network - its due to TIA and after a few reboots of TIA and the VM, changing network adapters etc - eventually TIA pops up with a screen saying the network adapter needs another network address assigned to it (like .254 or .255) - I click yes do this and press it then finds devices.......

But like I say it doesnt happen often and I dont know why and I cant find a way to force it to bring up the pop up to assign another IP to the adapter......

It will then work for weeks/months before it happens again......

One of life's mysteries.....

 

[Rob...]

@505bloke

Sounds like the pc/pg isn't set correctly. Also, TIA will only ask to assign another IP address, if the local NIC isn't in the same range as the target.

 

[joseph_e2]

Another gotcha to look out for is corporate IT policies and firewall settings. I've had issues with the "discovery" function of both the AB and Siemens software packages on my company laptop. Whether the software is in a VM or on the host. Whether the USB Ethernet adapter is connected to the VM or the host. Even with the corporate IT policies not applied to the VM directly but only on the host.


They're doing something at a very deep level inside the group policy settings that interferes with the broadcast messages that the software uses to discover modules. At first, for example, it worked for me but after some update a very long time ago, it just stopped working. No matter what I did, I couldn't get it to work, so I stopped trying.



In the Siemens world, I could usually get it to work with the Serial/USB PC Adapter being connected to the VM, but, again, it wasn't always reliable. I could never get it to work over Ethernet at all unless the software already knows the IP address.