Simatic S7-1500 Can't Reach Managed Switch

[ehhakeoiiijge]

I have a managed ethernet switch with a tested/good configuration and the only device it can't reach is a Simatic S7-1500.

If I connect my PC ethernet directly to the S7 I can ping the PLC and go online in TIA. Everything is OK.

If I connect any other device (PC, AB PLC, Prosoft Module) to the S7's port on the managed switch, the networking works OK. That confirms to me that the switch is configured correctly.

I tried to enable and configure the "Router" field in TIA > PLC > Ethernet Settings > IP Protocol by adding the appropriate gateway address for the switch. That had no effect.

Any ideas for troubleshooting?

 

[AlfredoQuintero]

Try using the Siemens PRONETA or the ProfinetCOmmander. These programs support DCP detection, which does not use IP. if you can detect the S7-1500 with either of these programs you can verify the IP setting of the S7-1500 and may be able to figure out why it cannot be reached by IP based protocols.

 

[ehhakeoiiijge]

Try using the Siemens PRONETA or the ProfinetCOmmander. These programs support DCP detection, which does not use IP. if you can detect the S7-1500 with either of these programs you can verify the IP setting of the S7-1500 and may be able to figure out why it cannot be reached by IP based protocols.

Thank you. I tried Siemens PRONETA with direct ethernet connection from PC to S7 PLC. Network settings looked correct: IP, subnet mask, router OK.

Then with S7 PLC connected to switch and PC connected to switch, there is no connection in PRONETA.

Screenshots attached.

Anything else to test in PRONETA?

 

[Puddle]

Could it be a conflict? Try changing your setting to a different address and ping it first to ensure it's not being used. That's very close to the default IP and it's on the default subnet mask.

 

[AlfredoQuintero]

I am not sure if the problem is a conflicting IP address, because the DCP protocol does not use Internet protocol and yet PRONETA does not detect the S7-1500 when connected through the switch.

Could this be a lower level kind of problem?

What is the color of the switch's LED for the port connected to the PC and the port connected to the S7-1500?

Is the port connected to the PLC set to automatic baud rate recognition? Is the S7's Ethernet port set to automatic baud rate recognition? I would try to rule out first baud rate issues.

If the switch is set to automatic, try setting it manually to 100 MBPS full duplex.

 

[mk42]

If the switch is set to automatic, try setting it manually to 100 MBPS full duplex.

Absolutely a good thing to check, but then change it back, because everything Siemens is autonegotiate out of the box

 

[mk42]

I have a managed ethernet switch with a tested/good configuration and the only device it can't reach is a Simatic S7-1500.

If I connect my PC ethernet directly to the S7 I can ping the PLC and go online in TIA. Everything is OK.

If I connect any other device (PC, AB PLC, Prosoft Module) to the S7's port on the managed switch, the networking works OK. That confirms to me that the switch is configured correctly.

I tried to enable and configure the "Router" field in TIA > PLC > Ethernet Settings > IP Protocol by adding the appropriate gateway address for the switch. That had no effect.

Any ideas for troubleshooting?

Can it talk to other 1500's? It could be that the "tested good" configuration is good for everything except Siemens.

• What features are you using?
• What is the switch manufacturer; did you enable priority tags (for Profinet) in the switch if needed?
• Is there any firewall causing issues?
• What subnets are involved; is there a layer 3 transition between one side of the switch and the other?

 

[ehhakeoiiijge]

@Puddle: I just confirmed that there is no IP conflict.

@AlredoQuintero: PC and S7 switch ports both flashing green (normal). S7 link light is flashing green and yellow (alternating). That switch port has Speed (Auto, 10Mb/s, 100Mb/s) and Duplex (Auto, Half, Full) settings. It is set to Auto, Auto.

@mk42: I am using the AB (Cisco) Stratix 5700 with a full license (enables routing).

The switch is only doing VLAN routing between two subnets (192.168.0.x and 192.168.1.x). The S7 port is NOT being routed- it is on the same VLAN/subnet as the switch (switch is at 192.168.1.1 which I use for the gateway address). FWIW, the routing features are working for the devices which are on other subnets.

The switch also has "Smartport" optimization presets on the ports to optimize traffic for the device type (Desktop, Automation Device). Changing or disabling the smart port preset doesn't change my results.

There is no firewall interference. I am testing with the S7 and switch connected directly. I am testing the connection through the switch's command line interface (via serial programming port) so it's not passing through anything else.

Profinet traffic is enabled by default on my switch firmware version. See attached screenshots showing the relevant section in the manual and the port configuration with Vlan0 enabled.

 

[Ken Moore]

Was this PLC, once on the network, on a different port or switch? I know with 300 series Siemens switches, if you use Mac assignments per port, the system will not allow you to move devices to a new switch unless you delete the entry on the the old switch. Even if the new switch does not have port assignments. The MASTER switch knows.

 

[ehhakeoiiijge]

UPDATE: It's working!! Thank you all for the direction in troubleshooting.

@mk42: Your comment led me to look into Profinet compatibility with the switch and this thread: http://www.plctalk.net/qanda/showthread.php?t=115112

The solution in my case was to set that S7 port for Voice traffic. That seems to handle Profinet better than using default or Automation-optimized settings. I changed to Voice traffic in both Smartport settings through the WebUI and running the CLI command mentioned in the thread above.

 

[mk42]

UPDATE: It's working!! Thank you all for the direction in troubleshooting.

@mk42: Your comment led me to look into Profinet compatibility with the switch and this thread: http://www.plctalk.net/qanda/showthread.php?t=115112

The solution in my case was to set that S7 port for Voice traffic. That seems to handle Profinet better than using default or Automation-optimized settings. I changed to Voice traffic in both Smartport settings through the WebUI and running the CLI command mentioned in the thread above.

Yeah..... "automation optimized" means something very different for EIP and PN, sadly.


Glad you got it sorted out!

 

[AlfredoQuintero]

UPDATE: It's working!! Thank you all for the direction in troubleshooting.

@mk42: Your comment led me to look into Profinet compatibility with the switch and this thread: http://www.plctalk.net/qanda/showthread.php?t=115112

The solution in my case was to set that S7 port for Voice traffic. That seems to handle Profinet better than using default or Automation-optimized settings. I changed to Voice traffic in both Smartport settings through the WebUI and running the CLI command mentioned in the thread above.

This is very useful information. Thanks for sharing your solution. Glad to read that you have fixed your problem.