FB_COUNTER

Description Function Block

The FB_COUNTER function block is used to implement an incrementing and decrementing counter. The ActValue specifies the current internal counter value. The counter can be parameterized by means of the PresetValue and CounterLimit inputs.

For a logic 1 signal at the bReset input, the internal counter value is set to the value which is parameterized by means of PresetValue. For a rising edge at the bCountUp input, the internal counter value is incremented by 1. For a rising edge at the bCountDown input, the internal counter value is decremented by 1. As soon as the counter value specified in CounterLimit is reached, the bCounterOut output is set. When the counter value reaches 0, the bCounterZero output is set.

When the TwinSAFE group is started (Run=1), ActValue is set to PresetValue. When the group is stopped, ActValue is set to 0.

EL6900

The FB_COUNTER function block is not supported by the EL6900.

Table 38. VAR_INPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bReset`	`BOOL`	`FALSE`	Rising edge resets the counter to the `PresetValue` value.
`bCountUp`	`BOOL`	`FALSE`	Rising edge increments the internal counter value by `1`.
`bCountDown`	`BOOL`	`FALSE`	Rising edge decrements the internal counter value by `1`.
`PresetValue`	`SAFELINT`	`0`	Initialization value to which the counter is set at Reset. Only a constant value is permitted (no variable)
`CounterLimit`	`SAFELINT`	`0`	When this value is reached, the `bCounterOut` output is set to `TRUE`. Only a constant value is permitted (no variable)

Table 39. VAR_OUTPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bCounterOut`	`SAFEBOOL`	`FALSE`	Set to `TRUE` when the internal counter value has reached the value of `CounterLimit`.
`bCounterZero`	`SAFEBOOL`	`FALSE`	Set to `TRUE` when the internal counter value is less than or equal to `0`.
`ActValue`	`SAFEUSINT`	`0`	Current value of the internal counter value Permitted data types: `UINT`, `INT`, `UDINT`, `DINT`
`bError`	`SAFEBOOL`	`FALSE`	`TRUE`: The `ActValue` output has an overflow or underflow. `FALSE`: No error has occurred.