Range and attenuation

[mazeroth]

Could someone please explain the differences of these two detector settings on a 5890/6890? My trainer didn't have a clue. Or, if you have a link that describes them that will work as well.

Thanks in advance!

[AICMM]

If I remember correctly and I don't have my manuals in front of me, range will change the signal output by a factor of 10 and attenuation will change the signal output by 1/2(n). When I am back in front of my manuals I will confirm.

Best regards.

[cgianoli]

afaik range selection was 2^x where x is the number that you can select.
with range 0 you have maximum sensitivity. If you select range 8 (2^8=256) your signal output was 256 times less sensible.

The attenuation isn't use, the only use that I know is if you have a registrator with analogical signal input... I think that now all use PC controller software or sometimes integrator. The parameters are the same as range (2^x), if you try to use the output signal don't change (on a normal PC output).

[mazeroth]

Thanks for all the input so far but if I could get a for certain answer I would greatly appreciate it! I'm the type that loves to know how things work and why.

Thanks again.

[skunked_once]

Here is a link for a pdf copy of the 5890 manual. Explanation of the signal outputs starts on page 72.

http://ipes.us/used/58904.pdf

[GasMan]

The range and attenuation controls are only used with an analog signal output. They are not used with digital signals that would be sent using either the LAN or HPIB to a data system.

You have in the GC an amplifier that is used to amplify the signal from the detector to your output device. It is possible for the signal from your detector to be too large for your amplifier, this means that the amplifier can no longer amplify the signal. This would result in a flat top peak. The RANGE controls the input to the amplifier, so if you see flat top peaks, increase the range. The attenuation controls the output of the amplifier and is used then to keep signal on scale for your data handling device.

Hope this helps.

Gasman

[mazeroth]

Thanks to everyone for their input. I totally understand it now. I couldn't find our 6890 manual and after reading the 5890 pdf that was linked I found the 6890 manual (figures, right?). We have some of our 6890s hooked up only via the digital. Some of them have Waters brand eSATIN boxes which takes the analog signal and amplifies it by a factor of around 1000 (which the range does have an impact on). It's the stupidest thing I've ever seen but our management doesn't like seeing areas sometimes around 2, even though they're actually something like 2.1324, but they took the decimals off by default when we process. We use Empower to capture our chromatograms, which sucks. Oh, how I wish we used Chemstation.

[Jumpshooter]

I feel your pain Mazroth: I wish I had Chemstation here also, but we are stuck with Turbochrome. I'm sure a poll of chromers would show Chemstation as the "preferred" data capture/processing s/w.

[JGK]

I feel your pain Mazroth: I wish I had Chemstation here also, but we are stuck with Turbochrome. I'm sure a poll of chromers would show Chemstation as the "preferred" data capture/processing s/w.

That's funny, we have both Chemstation and Empower within our facility. Given the choice, every one of my analytical technicians would junk Chemstation in favour of Empower.

[chromatographer1]

Jumpshooter,

A lot of workers have been forced to use Chemstation over the years.

You usually like the software you presently use and the way it works in comparison to software that works in a different manner that you have never used or seen before.

But with untrained workers, I have found that there are many software packages which seem to have a better reception, not that Chemstation won't get the job done.

Rodney George
consultant

[Peter Apps]

Chemstation is fine for what is is optimised for; routine analyses using standard methods. Get into method development, hardware tinkering and exploratory work and it makes life harder than it needs to be.

Peter

[chromatographer1]

Very well put, Peter, and your statement fits my experience PERFECTLY.

Rodney George

[Peter Apps]

Thanks Rodney, it's a subject that has been aired before; how instruments and hardware are becoming more and more specialised for routine analyses. It would be a huge benefit for the tinkerers if the various interlocks, passwords, audit tracking etc could just be turned off, and if there was a way of directly accessing control of the instrument without being limited by the pre-set options.

I suppose that we can dream

Peter