Question Lights out on switch - lights on on device?

[Swo1e]

Hey Guys - We are having a networking issue with an experimental machine in the automation industry. The problem stems from a RFID reader communicating ISO-15693 tag codes to our machine PLC. The reader is connected to the machine LAN switch via ethernet interface. I'll spare most of the details for now but after several reads, the reader stops transmitting the data to the switch. The telling sign that we know that this is happening is that the up/down lights on the switch will turn off on the port the ethernet cable is plugged into, but the lights remain lit on the ethernet jack on the reader. The same will happen when connected directly to a laptop; bypassing the machine LAN. My question is what are some circumstances where the lights on a switch will turn off but remain lit on the device?

 

[SamirD]

Interesting problem. The only circumstances I have seen oddball behavior like this is when the device nic is locking up. There is a very slim chance that it is an incompatibility between the device nic and the switch, but I highly doubt it. More likely is one of the configuration settings on the nic is conflicting with the code that is using the nic for communications (sounds like some sort of buffer overrun or a pointer falling off the end of an array, but that's just a wild guess). Hopefully this helps.

 

[WaCableTech]

Hey Guys - We are having a networking issue with an experimental machine in the automation industry. The problem stems from a RFID reader communicating ISO-15693 tag codes to our machine PLC. The reader is connected to the machine LAN switch via ethernet interface. I'll spare most of the details for now but after several reads, the reader stops transmitting the data to the switch. The telling sign that we know that this is happening is that the up/down lights on the switch will turn off on the port the ethernet cable is plugged into, but the lights remain lit on the ethernet jack on the reader. The same will happen when connected directly to a laptop; bypassing the machine LAN. My question is what are some circumstances where the lights on a switch will turn off but remain lit on the device?

 

[WaCableTech]

Wrong power supply is the one I see most commonly, someone has multiple devices from same company, and the DC ports fit in both devices but has different ratings on the PSU. One will be 12V with 1.5 Amps the other 12V with 0.5 amps and when you mess that up the lower device can still pull 0.5 amps from the 1.5 amp PSU but the other device cannot pull 1.5 Amps from the 0.5 Amp PSU. oops. Been called out in middle of night for that a few times, everyone says same thing no one touched that how could that happen must have bene like that for years, are you going to change me, that can't be the problem. Well, when I switched them everything started working right? That's the problem then, and Yes, we're going to charge you for messing up the POWER on YOUR equipment and calling us out in the pitch dark of night at 11PM for it.