Queues -- Chaining Methods Together
Methods can be chained together using the QUEUE feature from the main menu. Chaining can be useful in at least three situations:
- When there are more than 999 runs in a series (the maximum for any data name) the data name can be changed with a second Method that allows another 999 runs, etc.
- When two types of analyses are being conducted, a second Method can change any run parameters, including which detectors are enabled, detector filtering, and pump conditions.
- To slow down the pump once a series of runs has been completed (a SHUTDOWN Method).
DEFINING A QUEUE
To begin setting up a queue, open the QUEUE drop-down menu:
You can either load an existing queue or define a new one. Either way, a dialog box will appear:
Up to 20 methods can be chained together in the QUEUE listbox, each one occupying a line.
For each line in the listbox, enter a line number, the name of the Method to be run, the name of the data files to be saved, and the first and last run numbers of the sequence to be performed. The data filenames and run numbers in the listbox supersede those in the Method.
The tEQUIL entry allows you to program a time delay, in minutes, between Methods. This could be used, for instance, to allow the EC detectors to equilibrate, or to allow a new flowrate to stabilize. For most purposes, however, set the time to zero for immediate execution of the Method.
Enter a FILE PATH only to send data to a location different from the default data location. For most purposes, leave this section blank.
Use the ERASE .LOG feature to automatically erase any previous .LOG file when the Queue is started. Since the LOG file contains a record of each run, it's best not to erase it. Rather, rename the LOG file and archive it with the data.
If desired, SAVE the Queue by pressing the SAVE button. This opens a dialog for saving the Queue:
A Queue name can have any combination of characters and spaces, and will automatically be assigned a .BAQ extension. Report Queues, used for data processing, have a .QUE extension to distinguish them from Control Queues.
Names can theoretically be up to 127 characters long, including the path (thus, C:\BAS2\DATA\myqueue.baq = 24 characters). Some advanced procedures may require shorter names, so we recommend using names with total lengths (including the path) of less than 33 characters.
For display purposes, a queue name may be truncated somewhat in various places in the program.
To start the sequence of chained Methods, click the PROCESS QUEUE >> button. The Methods will begin running according to their individual directions. While the Queue is processing, a status box will indicate the current Method and the scheduled runs:
CHAINING A SHUTDOWN METHOD
The last Method in the queue can be a SHUTDOWN Method. This allows the pump to be slowed down after all the samples have run, thus conserving mobile phase. Note that the pump should be slowed down, not stopped: because of the potential for corrosion, pumps should never be shut down with mobile phase in the system.
To create a SHUTDOWN Method to slow the pump, create a method with a lower flow rate (PUMP GRADIENT SCHEDULE). Save this Method under the name SHUTDOWN, and add this name at the end of the Queue:
To start the sequence of Methods, choose the PROCESS QUEUE button. The Methods will run in sequence, each performing its appropriate number of runs. When the SHUTDOWN method is reached, it will make the appropriate changes to the pump, then maintain this new setting.
