GE 90-30/20/Micro Manual De Usuario

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

EQ

Equal

Test two numbers for equality.

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NE

Not Equal

Test two numbers for non-equality.

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GT

Greater Than

Test for one number greater than another.

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GE

Greater Than

or Equal

Test for one number greater than or equal to another.

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LT

Less Than

Test for one number less than another.

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LE

Less Than

or Equal

Test for one number less than or equal to another.

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RANGE

Range

Determine whether a number is within a specified range
(available for Release 4.5 or higher CPUs).

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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:

INT

Signed integer.

DINT

Double precision signed integer.

REAL

Floating Point

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).

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