Creating and Modifying Programs
Calculating in a Program

To use different values and signals in one program, Chromeleon lets you use the four fundamental operations of arithmetic and powers. See below for some examples:

Addition or Subtraction: Relative Sample Position

The two examples below refer to the ASI-100 autosampler. (For general information about this autosampler, refer to Hardware Installation  ASI-100 HPLC Autosampler Series in the Administrator Help section.)

  1. To determine that the vial that is five incremented positions away from the current position is always used as the sample preparation vial, use the following command line:

0.000 Sampler.PrepVial Position + 5

For example, if you are currently processing the sample from position RB3, the vial at position RB8 is used for sample preparation.

  1. If the autosampler is currently at a position in the RA ring, the following line takes you to the corresponding position in the RB ring:

0.000 Position Position + RB1 - RA1

Multiplication: Calculating the Volume

  1. To record the solvent volume, which is transported through the column while the current sample is processed, as a virtual channel use the following line:

 VirtualChannel_01.Formula Formula=pump.flow*system.retention

In addition, you have to define: VirtualChannel_01.FormulaMin and VirtualChannel_01.FormulaMax.

 Tip: 

Always set FormulaMin and FormulaMax after you have defined the formula.

Division: Ratio

  1. To determine the ratio of two channels, record the quotient of the two channels as virtual channel:

 VirtualChannel_01.Formula Formula=UV_VIS_1/UV_VIS_2

Powers: Calculating the radioactive decay

  1. Use the following formula to record a channel for a radioactive substance as if this substance would not decay:

VirtualChannel_01.Formula  UV_VIS_1 / 2.718**

 (-0.69314718*System.Retention/t½)

 

 Note: 

For detailed examples of the Virtual Channel Driver, refer to Practical Tips for Device Control Special Commands, Relays and Others  Program Examples for Virtual Channels.

 

Relational and logical operators: Trigger Commands

  1. Use the following condition to combine, for example, fraction collection:

Trigger FRACTION UV_VIS_1 OR UV_VIS_2 > 100

In the above example, fraction collection could start if a signal with a peak area larger than 100 mAU is recorded on either the UV_VIS_1 or the UV_VIS_2 channel.

The following operators are available for trigger commands:

 

Operator

Description

>

Greater than

<

Less than

=

Equals

AND

All parameters must fulfill a condition.

OR

Only one parameter must fulfill a condition.

NOT

Verifies that a parameter has no specified value.

XOR (=^)

Verifies that the values are different.

 

Dionex recommends using the Fraction Collection device driver to control fraction collection. For more information, refer to  Collecting Fractions.