FB_COMPARE

Description Function Block

The FB_COMPARE function block checks that the 2–5 analog inputs CompIn1 to CompIn5 are equal within a window of tolerance based on time and value. The b1oo2, b2oo3, and b3oo5 inputs are used to specify the number of inputs to be evaluated. The udiAllowedDeviation and tToleranceTime (ms) inputs specify the deviations and the time interval permitted between the input values. The bIsValid output returns a logic 1 if the comparison results in a positive value.

The CompOut output contains the 1st analog value which meets the comparison criteria.

The ERROR state is entered if an overflow or underflow occurs. Then the CompOut and bIsValid outputs are set to 0 and the bError output is set to 1.

EL6900

The FB_COMPARE function block is not supported by the EL6900.

Table 36. VAR_INPUT

Name	Data Type	Initial Value	Description, Parameter Values
`CompIn1`	`LINT`	`0`	1st analog signal for the comparison (1oo2, 2oo3, 3oo5) Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`CompIn2`	`LINT`	`0`	2nd analog signal for the comparison (1oo2, 2oo3, 3oo5) Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`CompIn3`	`LINT`	`0`	3rd analog signal for the comparison (2oo3, 3oo5) Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`CompIn4`	`LINT`	`0`	4th analog signal for the comparison (3oo5) Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`CompIn5`	`LINT`	`0`	5th analog signal for the comparison (3oo5) Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`b1oo2`	`SAFEBOOL`	`FALSE`	Comparison mode 1oo2: Only the first two inputs `CompIn1` and `CompIn2` are active. If both inputs are equal (within the permitted deviation), then the first input `CompIn1` is written to the `CompOut` output. In case of an error, the `CompOut` output is switched off and the `bIsValid` output is reset. Only a constant value is permitted (no variable). Only one of the `b1oo2`, `b2oo3`, and `b3oo5` inputs may be`TRUE`.
`b2oo3`	`SAFEBOOL`	`FALSE`	Comparison mode 2oo3: Only the first three inputs `CompIn1`, `CompIn2`, and `CompIn3` are active. If at least two inputs are equal (within the permitted deviation), then the first input with the valid value is written to the `CompOut` output. In case of an error, the `CompOut` output is switched off and the `bIsValid` output is reset. Only a constant value is permitted (no variable) Only one of the `b1oo2`, `b2oo3`, and `b3oo5` inputs may be`TRUE`.
`b3oo5`	`SAFEBOOL`	`FALSE`	Comparison mode 3oo5: All five inputs `CompIn1`, `CompIn2`, `CompIn3`, `CompIn4`, and `CompIn5` are active. If at least three inputs are equal (within the permitted deviation), then the first input with the valid value is written to the `CompOut` output. In case of an error, the `CompOut` output is switched off and the `bIsValid` output is reset. Only a constant value is permitted (no variable) Only one of the `b1oo2`, `b2oo3`, and `b3oo5` inputs may be`TRUE`.
`udiAllowedDeviation`	`SAFEUDINT`	`0`	Permitted deviation when comparing the inputs Only a constant value is permitted (no variable)
`tToleranceTime`	`SAFETIME`	`TIME#0ms`	Time frame (in ms) within which unequal values are tolerated. Only a constant value is permitted (no variable)

Table 37. VAR_OUTPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bIsValid`	`SAFEBOOL`	`FALSE`	`TRUE`: The values are equal (within the permitted deviation).
`CompOut`	`SAFEUSINT`	`0`	Output value: Corresponds to the first `CompIn` input value which fulfills the comparison. Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`. The data type must be selected according to the input data types.
`bError`	`SAFEUSINT`	`0`	`TRUE`: The `CompOut` output has an overflow or underflow. `FALSE`: No error has occurred.

Name

Data Type

Initial Value

Description, Parameter Values

bIsValid

SAFEBOOL

FALSE

TRUE: The values are equal (within the permitted deviation).

CompOut

SAFEUSINT

0

Output value: Corresponds to the first CompIn input value which fulfills the comparison.

Permitted data types: UINT, INT, UDINT, DINT. The data type must be selected according to the input data types.

bError

SAFEUSINT

0

TRUE: The CompOut output has an overflow or underflow.

FALSE: No error has occurred.