8 Replies Latest reply on Oct 6, 2017 2:56 AM by pziel

    How to prevent the sequence method to be up-dated after every sample run of my sequence table

    pziel

      When I start a sequence using openlab CDS the method is copied from the methods directory to the sequence directory to create a sequence method (I am fine with that),

      but every time a sample in the sequence(table) is analysed, the sequence method is over-written and I do not want that!

      According to page 29 of "OpenLAB CDS ChemStation Edition C.01.03 Tips and Tricks for GC Customers"  this only happens after data analysis, but switching data analysis of in the method doesn't prevent the sequence method to be up-dated.

      The reason I don't want the original method to be updated during a run is that at the end of my analysis-run the flows are not yet stabile and the actual flows are copied into the sequence method and used with the next analysis run, resulting in retention time shifts and in integration differences.

       

        • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
          ryoboyle

          I am not aware of any settings in the OpenLAB ChemStation software that would permit you to update acquisition parameters in the sequence method from run to run. To my knowledge, the only parts of your sequence method that should be getting updated while your sequence is acquiring are the Retention Time and Response Factor stored in the calibration table. These will update as specified in the Update RF and Update RT columns of your sequence table if you have the Sample Type identified as Calibration.

           

          You can double check to see if the acquisition parameters are actually changing by comparing the ACQ.txt files found in each run's *.D folder.

           

          Also, I added tags to this thread to make it easier to find.

            • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
              pziel

              Dear ryoboyle,

               

              I’ve responded to your questions on the Agilent Community forum, but was not able to attach a file to it, so I send it to you by mail,

               

              Best regards,

               

              Paul

               

              [REMOVED PERSONAL INFORMATION]

                • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
                  ryoboyle

                  Thanks Paul,

                   

                  I did receive the attachments and am seeing the PPIP flow value as well as the column 2 flow change from one data file's acq.txt to the next data file's acq.txt. One odd thing that I noticed looking at your data and your sequence is that the sequence template that you attached is specifying a completely different method than what is listed in your acq.txt files. You sequence has a method name of PAUZE_TCD.M while your acq.txt files are reporting that the acquisition method name is TOTC6.M. Maybe you just sent me the wrong sequence.

                   

                  For the issue of the acquisition parameters changing throughout the course of the sequence, this is definitely not an intended function of the software. It is possible that maybe there is a corruption in your local GC memory or in the method you are running. I would recommend starting off from a completely blank slate by creating a new method from the DEF_GC.M method and clearing the local memory of the GC. To clear the GC memory, power cycle the GC while holding down the clear button on the front keypad.

                   

                  Once you have done both of those things, I recommend testing the new method by first performing single run injections and see if the acquisition parameters change. While you are troubleshooting this it would be a good idea to save a copy of the acquisition method with the data file so we can reference it if needed. You can select to do this in the Run Time Checklist which is available in the Method dropdown menu in Method and Run Control.

                   

                   

                  Please let me know if you have any questions.

              • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
                valentinrusu

                When you start a sequence, the master method (located in the methods directory) is copied not to the sequence directory, but to the data directory, where it does indeed become the sequence method. I suppose I'm having a little trouble understanding what the problem you're describing is. What exactly changes from run to run that you wish didn't? Can you also post the Revision of OpenLAB CDS ChemStation you're using? In the software (not the OpenLAB Control Panel, but the analytical software itself), click Help > About and let us know the revision code listed on that window.

                  • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
                    pziel

                    don't see how I can ata

                    Dear Ryoboyle and Valentinrusu,

                     

                    First of all thanks for your quick responses. I will try to answer your questions in one reply.

                     

                    In 2013 our company chanced from Windows 2000 to windows 7 and we found out that it was not possible to install the Chemstation software A09.03 (used for controlling our Agilent 6890N natural gas analyzer) on this new OS/computer. We purchased and installed a software up-date to OpenLab Chemstation C.01.04 (and GC firmware to N.06.07) and that is when the problems began: running the same sample for a number of times using a sequence we noticed a retention time drift for the eluting peaks.

                     

                    Nor the company who installed the software up-date nor Agilent Netherlands where familiar with this phenomena and blamed it on leaks in the system. After monitoring the GC setting during several runs I found out that the method used (indeed saved in the data directory and not in the sequence directory) was altered during the sequence.

                     

                    I’ll attach a .zip file where you can find several data files, the method and sequence file and a picture of the retention time shift. I would like to draw special attention to the acq.txt files where you can observe the difference in column flow of column 2.

                     

                    We have tried several tricks to overcome this problem, but the only thing that we found that worked is using a pre-run macro, where we force the method to load the original method from the method directory, but this has some other draw backs and is not a very elegant solution.


                    So I hope you can provide me with another solution.

                    Best regards,

                     

                    Paul

                    P.S. I can not find how to attach a file to this response, so I will try sending it to you by e-mail.

                    • Re: How to prevent the sequence method to be up-dated after every sample run of my sequence table
                      pziel

                      Dear valentinrusu,

                       

                      I’ve responded to your questions on the Agilent Community forum, but was not able to attach a file to it, so I send it to you by mail,

                       

                      Best regards,

                       

                      Paul

                       

                      [REMOVED PERSONAL INFORMATION]