The software High/low switching works on the V, but whether you have the resistor in the board or the correct resistor is another question and depends on the enrichment you expect. If its a standard CNOS your probably switching  between ohms to between 13C and a 15N.  This is not going to work if your running 10-20% 13C through because it will put it off scale so you would need to buy and install the correct ohm R.

________________________________________
From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of gerard olack <[log in to unmask]>
Sent: Thursday, January 25, 2018 5:44 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] Delta V switching resistors

HI Brett--

The easiest way would be to set up different gas configurations for the
different resistor states, then set up corresponding methods--and switch
between methods during  a sequence.

take care,

gerry


On 1/25/2018 4:18 PM, Hill, Brett wrote:
> I should specify that I don’t mean an actual physical change of the resistors, but rather the switching in or out of a second resistor in parallel using the Isodat software.  My question is:  Has anyone had success switching back and forth between naturally abundant samples and highly enriched samples just by changing the amplification settings in the Isodat software, barring contamination issues from carry-over?
>
> Brett
>
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Geldern, Robert van
> Sent: January-25-18 3:14 PM
> To: [log in to unmask]
> Subject: Re: [ISOGEOCHEM] Delta V switching resistors
>
> Hi,
>
> What exactly is the question?
>
> The option itself is available in the ISODAT software but to use it you must have a second resistor physically installed on your board (what is normally the case in the standard CNOS setup that you order). You can either order the resistor you need (depends on what isotope ratio you are behind) through thermo or directly from the manufacturer. It can be installed by everybody having some basic practical experience with IRMS hardware.
>
> regards,
> Robert
>
>> Am 25.01.2018 um 23:06 schrieb Hill, Brett <[log in to unmask]>:
>>
>> Hello all,
>>
>> I am hoping to find someone out there that uses the switching resistors available in the Delta V to change signal amplification to allow analysis of both enriched and naturally abundant 15N and 13C.  I have a few questions about  your instrument set up.  Or maybe no one does this and we are the only ones who actually considered this sales gimmick as feasible?
>>
>>
>>
>> Brett Hill
>> Stable Isotope Lab
>> Agriculture and Agrifood Canada
>> Lethbridge Research and Development Centre
>> 5403 1st Av. S.
>> Lethbridge, AB.
>> T1J 4B1
>> 403-317-3455
> --
> PD Dr. Robert van Geldern
> Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) | GeoZentrum Nordbayern Schlossgarten 5 | 91054 Erlangen | Germany [log in to unmask] | www.gzn.uni-erlangen.de
> fon: +49-9131-85-22514 | fax: +49-9131-85-29294 | room: O 2.112 (office)
>