I'm running HP1100 with chemstation A8.03 and GBIB interface. I keep having this nice surprise at the morning;

sequence is "stuck" between runs, pump is just running gradient at t=0, blank screen and a text: Warning input signal out of range on the monitor. Nothing useful in the chemstation logbooks.

Any idea what has happened? I'm no expert on computers. But I believe this has something to do with the LC interface? Haven't got any decent help from agilent. I would highly appreciate any suggestions. Thank you.

If this is a "new" issue, it can't hurt to turn off the power to ALL modules, restart the computer, power on the modules (wait for the ALS module to finish initializing), then open the Chemstation online. What detector are you using, we've never had this happen at R&D or at QC?

This is something I have done after getting "stuck" with the sequence. I would like to know the source of the error since this was already a third similar unpleasant surprise. We are using normal VWD detector.

I have seen this problem with our Agilent 1100/Antek 8060 nitrogen detector. This error results when the signal from your detector goes above, or below, the level the 35900 A/D interface can handle. I believe this is -0.1 to +1.0 volts--or something like that. The system stops taking data, and stops the sequence, but the pumps continue to run. As a result, the system will not tolerate drift or extreme positive or negative responses.

I have not figured out a solution to turn the pumps off.

In the meantime, you MUST get your samples under control so the signal generated by the detector stays between the interface limits. Auto-zeroing, or balancing, the detector before every run may also help, if you can wire the system to do that.

This error does not appear on our system with a Agilent VWD that does not have the separate A/D converter box, so perhaps the final solution is a new Agilent VWD. I don't recall ever seeing an over-or under-range message on that detector during a sequence, but it must have happened with all the stuff I've put through it, and the system just dealt with it.

Thanks a lot Scott! That was wery useful! I haven't seen the problem for a while. Except once last week there was this error message on screen, but the sequence was completed and shutdown macro had turned the pump of correctly. This means that the 'over range signal' was received after the run and interface shouldn't have been receiving any data from the LC anymore?? I have checked the windows NT event viewer but there was no entries/error messages at that time. I use autozero at the beginning of each run. I have to check if there has been something atypical in the problem runs. I do have a wash step at the end of each run and the detector signal goes out of range (the wash solvent is highly absorbing).

I don't feel comfortable to leave any sequences running over weekend. If this problem appears the system will keep on pumping to drynes. Problem is i can't use any chemstation options (pressure limit/solvent filling calculators) to prevent this since this error kicks out from chemstation and windows!?

Thanks again!

I have also seen this error with the system going to standby gracefully.

This is not a Windows error, so it won't show in the NT Event Viewer. Probably in the logbooks, but I think I checked, and it doesn't appear there, either. It's been almost a year since I dealt with this system.

You should try testing the system to see if the pumps will shut off at the minimum solvent level you choose after the error happens. If it works, it should be safe to run over weekends. This error may defeat the software that calculates solvent used/remaining, so test carefully. I like this software better than minimum pressures, which didn't work very well for us. It is easy to keep the volumes current. I just set shut-off at 100 mLs, and then fill to 600, if I expect to use 500 or less.

It sounds like you can work with the problem, now that you know what's going on. Glad I could help a little bit!