Table Of Contents

Calculation Formula Options

Last Modified: August 20, 2020

Use standard math operators, functions, and constants to customize existing hardware channels in the system.

All formulas must adhere to the following rules:

  • Every formula must contain a reference to at least one channel.
  • Channel references must be contained within single quotes ('channel name').
  • Element-wise calculation will be done when one of the operands is a channel or the parameter is a channel.
  • Decimal separators on literal numbers must be periods. Alternative separators such as commas are not supported.

Refer to the following table for examples of formula formats that you can use to configure a calculated channel.

Table 1. Supported Formula Formats
Description Formula Format Example
Element-wise arithmetic addition 'channel name' + x 'AI7' + 1
'channel name x' + 'channel name y' 'AI7' + 'AI8'
Element-wise arithmetic subtraction 'channel name' - x 'AI7' - 1
'channel name x' - 'channel name y' 'AI7' - 'AI8'
Element-wise arithmetic multiplication 'channel name' * x 'AI7' * 5
'channel name x' * 'channel name y' 'AI7' * 'AI8'
Element-wise arithmetic division 'channel name' / x 'AI7' / 5
'channel name x' / 'channel name y' 'AI7' / 'AI8'
Apply the function to the channel element function('channel name') sin('AI7')
Arithmetic equation x + y * z / 'channel name' 2 + 3 * 4 / 'AI7'
Arithmetic equation (x + y) * z / 'channel name' (2 + 3) * 4 / 'AI7'
Number with scientific representation 'channel name' + 1.23e-5 'AI8' + 1.23e-5
Constant usage function(constant * 'channel name')

sin(pi * 'AI7')

See Supported Functions, Operators, and Constants table.

Unary minus -'channel name' -'AI7'
Unary plus (a no-op) +'channel name' +'AI7'
Power operator 'channel name'^x 'AI7'^3

Note: The data type for all numerics is double-precision, floating-point.

Refer to the following table for examples of formula elements that you can use to configure a calculated channel.

Table 2. Supported Functions, Operators, and Constants
Formula Element Signal Type Definition
Supported Functions sin Analog Sine
cos Analog Cosine
tan Analog Tangent
arcsin Analog Inverse of sine
arccos Analog Inverse of cosine
arctan Analog Inverse of tangent
abs Analog Absolute value of any number
log Analog Logarithm
log10 Analog Common logarithm (logarithm to base 10)
Supported Operators + Analog Addition
- Analog Subtraction
* Analog Multiplication
/ Analog Division
( ) Analog, digital Bracket; contents are evaluated first
^ Analog Calculate the base raised to the power of the exponent
< Analog Less than
> Analog Greater than
<= Analog Less than or equal to
>= Analog Greater than or equal to
= Analog, digital Equal
!= Analog, digital Not equal
& Digital Logical and
| Digital Logical or
~ Digital Negation
? : Analog, digital Ternary operator indicating condition ? valueIfTrue : valueIfFalse. The data type of valueIfTrue and valueIfFalse must be the same.
Supported Constants pi Analog Pi (π) constant
e Analog Natural logarithm base constant (𝑒)
true Digital Is TRUE
false Digital Is FALSE

Recently Viewed Topics