Chromatography Forum

We have 2 Agilent 6890 GCs with uECDs and use the HPIB interface. We have observed that if the Chemstation software that we're using is open and acquiring idle signal data that over about 2-3 days, the 6890 will display a "Signal Buffer Full 103/104" error and will essentially lock up the instrument and the computer/software. This doesn't happen to our LAN based 6890 systems, nor does it happen to our older 5890 using HPIB through its interface box.

Any ideas what is causing this?

This indicates the communication between the computer and GC was lost for a short time. If the GC sends a signal that it's buffer has data, the ChemStation should tell it to transfer the data from the signal buffer. If there is a communication problem the request is not completed, and the buffers fill with data. Check the GPIB cables from the GC to the computer, max 2 meter cables, clean connectors with IPA. Is computer and GC on same circuit? Ground noise between the two could cause communication problem. Using a UPS on the computer? Do no use a UPS on the GC because the switching of the oven power will screw up a UPS, but ground the chassis of the GC to the chassis of the UPS.

nimbi63: Thank you for your help. It appears that the issue was that the attached computer's BIOS settings had it in power saving mode even though the OS was set to never go into power saving.

Oddly, now we are seeing another error "Instrument power off/on detected. Please close and restart the instrument session to connect to the instrument."

Any thoughts?

It appears that the issue was that the attached computer's BIOS settings had it in power saving mode even though the OS was set to never go into power saving.

Not that I understand any of the above, but HP/Agilent has told us in the past that their software doesn't like screen savers, power saver software, etc.