Measurement Computing LogBook Series - Manual (Page 166)

LV-40 LogView 989592 Software Reference
Examples of Calculated Channels
Example 1: P1_CH14 > 23
In this example the user wants to use CALC_00 as a logic indicator based on the state of physical channel
P1_CH14; thus channel CALC_00 will read 1 or 0, depending on the value of the physical channel’s
reading.
The user created a calculation function: P1_CH14 > 23. The calculation channel is labeled CALC_00 as
seen in the following figure.
Assume P1_CH14 had a reading of 26.13. Since 26.13 is greater than the value 23 in the calculation
function, CALC_00’s reading would appear as 1.0. If the channel P1_CH14 reading drops to 23 or lower,
CALC_00 will read 0.0. Note that CALC_00 can be used in additional equations as will be seen in
example 2.
To obtain a calculation channel, select the Calculated Channel Configuration window’s Edit pull-down
menu, then select Add Channel. In regard to the calculation function column, the following steps
highlight how to enter the function used in this first example, i.e., P1_CH14>23.
1. Ensure the physical channel to be referenced is enabled. In this case: P1_CH14.
2. Use the Calc (y = fx) button in the toolbar or Calculated Channels from the View pull-down menu to
access the Calculated Channel Configuration Window.
3. Select the Edit pull-down menu (located on the Calculated Channel Configuration window).
4. Select Add New to add a calculation channel. In our first example this is CALC_00.
5. Click on the cell in the Calculation Function Column.
A F(x) button appears by the Enter Function Expression dialog box.
6. Use the F(x) button to access the Equation Assistance dialog box.
7. In the Equation Assistant box, double-click on the desired reference channel. P1_CH14. This entry
will appear in the equation box, located just below the title bar. Note that you may type the channel,
and other equation entries in this box, if desired.
8. From the Relational and Equality buttons (<=, >=, <, >, = =, !=) select the “greater than” symbol (>).
This entry will appear in the equation box.
Equation Assistant Dialog Box
9. With the cursor placed after the greater than symbol (>), type 23.
10. Verify that your function appears correctly and click the button. Validate will verify that
you have a useable equation and will inform you when there is a problem with an equation. For
example, you may have a missing parenthesis.
11. If necessary, correct your equation and validate the new one.
12. Click the button. This closes the Equation Assistant.