Chromatography Forum

We have a 6890N that is controlled entirely via a network connection (i.e., there is not local workstation for it). The network Win 7 workstation controlling it is running the EZChrom version of OpenLab. We purchased the license/driver to do this from Agilent. It works fine, except every Friday at about 2:30 PM the instrument disconnects. After a few minutes it reconnects and all is fine. So we cannot have anything running during this time. The errors in Win 7 event viewer are:

6890 at 192.168.20.220 (the instrument's network address) went offline unexpectedly.
Winsock error number 79 Unable to get response from the instrument.
Winsock error number 274C Could not establish low-level connection.

The errors in the OpenLab event log are similar.

I've carefully checked the Win 7 Task Scheduler. Nothing is set to run at that time. No antivirus software is installed on the workstation. I've had IT look at this. They've assured me there is nothing they're doing on the network at this time and could offer no other ideas. I've monitored the Microsoft utilities Process Explorer and Process Monitor at the time. Other than seeing the event happen, I don't observing anything triggering the problem. The workstation has three network cards: one for local GC it controls, one for the intranet, over which the 6890N is controlled, and another to control the CTC PAL for the local GC.

Anyone see anything like this before or have any suggestions?

May be your PC power management intrudes (set the power profile to max performance).
Other reason may be GC data buffer overflow. Not sure about EzChrom, but Chemstation constantly exhausts all the GC signal buffers,

... It works fine, except every Friday at about 2:30 PM the instrument disconnects. After a few minutes it reconnects and all is fine. So we cannot have anything running during this time...

I don't know if it would be possible in your environment, but what if you advance RTC in your local machine to Friday, let's say 1 PM and see if it looses connection.
At least you would know if it's your machine feature or resetting comes "from the network".

It works fine, except every Friday at about 2:30 PM the instrument disconnects.

Anyone see anything like this before or have any suggestions?

The 6890N is on summer work schedule, and is planning for the weekend !

Thanks for the responses.

@antonk: Yes, that can be a problem. All our workstations are set to Max performance. If we reboot the GC and workstation at 2 PM, and without collection any data, it still disconnects. I would hope buffers wouldn't fill that quickly!

@dblux_: OK, yes, that's a good suggestion. We can do that and we'll give that a try and see what happens.

@Consumer Products Guy: Early release!!!

@Consumer Products Guy: Early release!!!

Yeah - I got early release: released 1.5 years before planned retirement !!!

An update on dblux_'s suggestion. Last Friday it disconnected as usual around 2:30 PM. Re-set the PC workstation's clock to 1 PM, rebooted and re-established connection. Waited until the PC clock read 3 PM. No disconnect. Yesterday set the PC workstation's clock to Friday, July 28, 1:30 PM. Rebooted and reconnected. Waited until the apparent time of 3:30 PM. Again, no disconnect. It doesn't seem like the workstation's the issue here.

.... It doesn't seem like the workstation's the issue here.

You will have to discuss it with IT people.
You may execute "ipconfig /all" command from the command prompt and check "Lease expires" date whether it is set for nearest Friday 2:30 PM.
Maybe it is DHCP server configured to renew leases every Friday ? - task for IT people

Another thing to consider is power problems. If something nearby powers up or down at that exact time each week, then it could be causing enough of a power fluctuation to cause the disconnect.

I used to live next to an electroplating shop, and every morning at 5:30 my alarm clock would reset, nothing else in the house was affected. When they turned on the electroplating baths in the morning it would cause just enough of a current drop in my apartment building to reset my clock.

@dblux_: Thanks. Forgot about that. Interestingly, the renew is scheduled for this Friday, but at 10:30 PM. I did release/renew and confirmed with the time-stamp that it had renewed. Interesting during that process connection to the GC was not lost. But it did give a new renew time, pushing it to Saturday. So we'll see if it disconnects at the usual time today.

@James: Good suggestion. Each of our GCs are on their own dedicated line, and in all may years of doing this, this building has the cleanest, best power. But I'll keep an eye on this.