Section 5 – Recorder Setup
5.1.3.5Calculated Input
Any of the eighteen channels can be a calculated channel. A calculated channel gets its value from a series of calculations, which may be based on one or more live channels. Setting a live input channel to be a calculated channel will disable the live input. It is recommended that the virtual channels (Channel 7 to 18 in a 6 input unit or Channels 13 to 18 in a 12 channel unit) be assigned as calculated channels.
The Calculated Channel Setup dialog window has some powerful options. The user can set up 6 constants (X,Y,Z,I,J,K) to be used in the calculation and can define up to 6 functions (F1 to F6). The calculation can contain live inputs (C01 to C06 – Channels 1 to 6 for a 6 channel unit, or C01 to C12 – Channels 1 to 12 for a 12 channel unit), or other defined channels C01 to C18. The icons are defined as
Delete Button | Test Button |
Constants: This allows the user to set a constant value, eg 3.41592 to a variable, say X, then use this in an equation by simply selecting the X. This is useful for coefficients and the like. To set the constant, check the Set Const. box, then touch any of the entry boxes to the right of the constant buttons. Use the numeric keys to enter the value. The ◄ and ► buttons will move the cursor, the Del button will delete the character to the left of the cursor and Clear button will erase all digits. When complete UNCHECK the Set Const. box. You can now use the constants by simply selecting the button. In the example shown right, pressing the X button will insert X into the equation, which is equivalent to 3.41592.
Clear Button | Exit Button |
Figure 5-5 Calculated Channel Setup
Functions: This allows the user to define up to six functions for use in the calculations. To set up a function, check the Define box, then press the Function button, say F1. The input line will show F1=, continue to enter your formula using the available buttons. The ◄ and ► buttons will move the cursor, the Delete button will delete the character to the left of the cursor and Clear button will erase all digits. Once you have entered the function press the Enter button. (The Test button will change to Enter when you first select a Function key.) When you are done UNCHECK the Define box. You can now test your function or use it in the calculated channel.
Calculations: The calculations entered here will be assigned to the channel being set up. The calculations can use any of the 18 channels (C01 to C18), any of the six functions, any of the six constants, and the math functions. Make use of the parenthesis buttons to ensure your formula is interpreted correctly. The ◄ and ► buttons will move the cursor, the Del button will delete the character to the left of the cursor and Clear button will erase all digits. Once complete, it is necessary to test the function for accuracy by pushing the Test button. This will bring up the Test dialog as shown below. Once the calculation has been fully tested, press the Done button to return to the Calculated Channel Setup window and then press the Exit button.
Min, Max, Avg: The functions Min, Max and Avg use the MINimum, MAXimum or AVeraGe of a channel input in the calculation. The Average is a weighted average = (last value + current value)/2. The format is MAX(C02)+MIN(C03) for the maximum value of channel 2 plus the minimum value of channel 3. If Min, Max or Avg is used in an equation a reset dialog will appear upon exit. See below.
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