GE 90-30/20/Micro manual Relational Functions, Abbreviation Function Description

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Section 4: Relational Functions

Relational functions are used to compare two numbers. This section describes the following relational functions:

Abbreviation	Function	Description	Page
EQ	Equal	Test two numbers for equality.	4-41
NE	Not Equal	Test two numbers for non-equality.	4-41
GT	Greater Than	Test for one number greater than another.	4-41
GE	Greater Than	Test for one number greater than or equal to another.	4-41
	or Equal
LT	Less Than	Test for one number less than another.	4-41
LE	Less Than	Test for one number less than or equal to another.	4-41
	or Equal
RANGE	Range	Determine whether a number is within a specified range	4-44
		(available for Release 4.5 or higher CPUs).

Relational functions are used to determine the relation of two values. When the function receives power flow, it compares input parameter I1 to input parameter I2. These parameters must be the same data type. Relational functions operate on these types of data:

Data Type

Description

INT	Signed integer.
DINT	Double precision signed integer.
REAL	Floating Point

Note

The REAL data type is only available on the 350 and 360 series CPUs, Release 9 or later, or on all releases of CPU352. Also, the Range function block does not accept REAL type. Additionally, the %S0020 bit is set ON when a relational function using REAL data executes successfully. It is cleared when either input is NaN (Not a Number).

The default data type is signed integer. To compare either signed integers, double precision signed integers, or real numbers select the new data type after selecting the relational function. To compare data of other types or of two different types, first use the appropriate conversion function (described in section 8, “Conversion Functions”) to change the data to one of the supported types.

If input parameters I1 and I2 match the specified relation, output Q receives power flow and is set ON (1); otherwise, it is set OFF (0).

	_____
(enable)
	INT
(input parameter I1)	—I1	Q— (output parameter Q)
(input parameter I2)	—I2

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GFK-0467K Chapter 4 Series 90-30/20/Micro Instructions Set 4-41