Yet Another Agilent 6890N LAN Issue

Discussions about GC and other "gas phase" separation techniques.

8 posts Page 1 of 1
We have a 6890N that's behaving rather strangely. It will routinely fail to connect or disconnect from the MassHunter instance. When pinging it, about 50-75% of the pings aren't coming back, so it appears to be haphazardly losing packets. It has gotten worse over the past week, where I was earlier seeing 25-50% packet loss. I've tried swapping both the Ethernet cables and the switches for known good units, which doesn't seem to fix the issue.

Also rather strange is that all of our other GC-MS's indicate a 100 Mbit/s connection at the switch when plugged in. This problematic 6890N only lights up the 10 Mbit/s connection LED.

There's no issue with the 5973 Network MSD that's attached to it, which is behaving normally.

I still haven't been able to fix my last 6890N LAN issue, which was similar but was a complete comms failure, rather than this instance which is a partial failure (but bad enough to prevent setting up runs).
I can't remember if the first 6890Ns were 10MB or 100MB communication cards but it could be the LAN port or the communication card is going bad. Does that one have the Jet Direct card or is it a built in type of connection?
The past is there to guide us into the future, not to dwell in.
James_Ball wrote:
I can't remember if the first 6890Ns were 10MB or 100MB communication cards but it could be the LAN port or the communication card is going bad. Does that one have the Jet Direct card or is it a built in type of connection?

This is a unit with a direct connection.

Interesting development since I posted this yesterday - this instrument and its PC runs off the same switch as another GC-MS and PC. The other instrument has no issues communicating. When I put the problematic instrument on its own switch, the comms no longer drops out.

For clarification - in my earlier post I'd said I'd already swapped out the switch, but what I meant was that the existing switch was working just fine with another instrument, so I'd assumed it wasn't likely to be the cause of the issue. Sorry for the error!

For some reason then, the 6890 doesn't like that switch, even though it's of a similar vintage. Changing the port on the switch and the cable makes no difference. The other instrument and the MSD and PCs on that switch all talk fine.

With this in mind, it wouldn't surprise me if the 6890 has a 10 Mbit/s-only card in it and what I thought was a fault condition may just be due to the fact that it's older.
wss wrote:
...Also rather strange is that all of our other GC-MS's indicate a 100 Mbit/s connection at the switch when plugged in. This problematic 6890N only lights up the 10 Mbit/s connection LED.
...

6890N is 10Mbit/s
dblux_ wrote:
wss wrote:
...Also rather strange is that all of our other GC-MS's indicate a 100 Mbit/s connection at the switch when plugged in. This problematic 6890N only lights up the 10 Mbit/s connection LED.
...

6890N is 10Mbit/s

I thought it might be. Not sure why it's not behaving on the switch. The other equipment seems okay with it regardless of connection speed.
wss wrote:
I thought it might be. Not sure why it's not behaving on the switch. The other equipment seems okay with it regardless of connection speed.


Once I replaced LAN card in 6890N. It was defective. Initially it was OK, but after a couple of minutes it was loosing connection.
Just some guesses:
Could it be an IP-adress issue?
Maybe for some reason, the IP of the card has been reset (or BOOTP/DHCP is not working anymore) and is now generating conflicts with another system on that switch? (and would work if nothing else is on that switch)

I would check the IP adresses and ARP tables of all systems and PCs and look for conflicts.

Maybe assign another IP adress and test if it makes a different.

Another thing would be to scan the traffic on that LAN segment. Maybe another system if flooding the LAN, preventing a steady connection to this system.

Another thing to check is for network loops.
I have had switches loose a single port before and be difficult to diagnose. Also a cable can have a bad connection in it and just suddenly stop working.

I also had one GC that would randomly disconnect and placing it on a large UPS fixed the problem, apparently there was a problem with the power coming in on the line that the UPS compensated for.
The past is there to guide us into the future, not to dwell in.
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