Calculation Formula Options

Version:

Last Modified: December 9, 2019

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
Element-wise arithmetic addition	'channel name x' + 'channel name y'	'AI7' + 'AI8'
Element-wise arithmetic subtraction	'channel name' - x	'AI7' - 1
Element-wise arithmetic subtraction	'channel name x' - 'channel name y'	'AI7' - 'AI8'
Element-wise arithmetic multiplication	'channel name' * x	'AI7' * 5
Element-wise arithmetic multiplication	'channel name x' * 'channel name y'	'AI7' * 'AI8'
Element-wise arithmetic division	'channel name' / x	'AI7' / 5
Element-wise arithmetic division	'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

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