S7Guy
Member
I ran into a very strange problem recently.
I was at a site that has eight S7-416s. They are all connected via Ethernet to one central server running Windows 2000. There are also seven other HMI consoles running NT, plus three more Simatic TI PLCs. Siemens Softnet runs on the server, and provides the connection between the PLCs and the consoles.
Well, I was called into the plant because all of the consoles suddenly became non-responsive. As part of my troubleshooting, the first thing I did is try to ping the various devices in case some piece of hardware failed (i.e. a hub loses power). This is what I found: I could ping all of the consoles and the TI PLCs from the server, but none of the Siemens PLCs. I went to a console, and could ping the server, the TIs and the other consoles, but still not the S7 PLCs. I use static IP addresses on the server and consoles, and I did an IPCONFIG to verify that nothing had changed.
I opened the cabinets on the PLCs, and there were no fault lights. I powered one off and on again, and I was then able to ping it. I did this to each PLC, and they were back in business within a few minutes.
Afterwards, I checked the Module Diagnostics, and there were no power outages or anything else out of the ordinary in the event history.
Can anyone thing of anything that would cause ONLY the Siemens S7 PLCs to become disconnected? The plant had been operational for years, so there aren’t any IP or MAC address conflicts for sure (I did all of the programming and configuration). The only hint that I have is that it’s possible that someone in the IT department was doing maintenance on other computers on the same network (it was on a Saturday), but I can’t imagine there is anything they could have done to cause this behavior.
I was at a site that has eight S7-416s. They are all connected via Ethernet to one central server running Windows 2000. There are also seven other HMI consoles running NT, plus three more Simatic TI PLCs. Siemens Softnet runs on the server, and provides the connection between the PLCs and the consoles.
Well, I was called into the plant because all of the consoles suddenly became non-responsive. As part of my troubleshooting, the first thing I did is try to ping the various devices in case some piece of hardware failed (i.e. a hub loses power). This is what I found: I could ping all of the consoles and the TI PLCs from the server, but none of the Siemens PLCs. I went to a console, and could ping the server, the TIs and the other consoles, but still not the S7 PLCs. I use static IP addresses on the server and consoles, and I did an IPCONFIG to verify that nothing had changed.
I opened the cabinets on the PLCs, and there were no fault lights. I powered one off and on again, and I was then able to ping it. I did this to each PLC, and they were back in business within a few minutes.
Afterwards, I checked the Module Diagnostics, and there were no power outages or anything else out of the ordinary in the event history.
Can anyone thing of anything that would cause ONLY the Siemens S7 PLCs to become disconnected? The plant had been operational for years, so there aren’t any IP or MAC address conflicts for sure (I did all of the programming and configuration). The only hint that I have is that it’s possible that someone in the IT department was doing maintenance on other computers on the same network (it was on a Saturday), but I can’t imagine there is anything they could have done to cause this behavior.