====== Counter ======

{{:en:mervis-ide:35-help:bd30.png}}

===== Block name =====

BD30_COUNTER

===== ST call =====

<code st-iec>
PROGRAM BD30_COUNTER_DEMO
 VAR
 L1: LINT;
 FB1: LIB.CORE.V1_0.BD30_COUNTER;
 FB2: LIB.CORE.V1_0.BD2_PULSE_GENERATOR;
 END_VAR

 FB2();
 FB1(BX := FB2.OUT);
 L1 := FB1.OUT;

END_PROGRAM
</code>

===== Library =====

LIB\CORE

===== Version =====

V1.0

===== Description =====

The block is a pulse counter. Number of pulses is brought to the output //OUT//. The //OUT// value may be increased by 1 at rising edge on the //BX// input, or at falling edge of the //BXF// input. It may be also decreased by 1 at rising edge on the //BXD// input, or at falling edge of the //BXDF// input. The //MINIMUM// parameter specifies the lower limit of the counting range of //OUT,// while //// //MAXIMUM// is the upper limit. All possible values are thus //MINIMUM,MINIMUM+1,MINIMUM+2,...,MAXIMUM-1,MAXIMUM//. The behaviour at MINIMUM and MAXIMUM is given by the parameter //BRING//:

  * //BRING=TRUE//: Ring (cyclic) counter. If //OUT=MAXIMUM// and the value has to be increased, then it starts at //MINIMUM//. If //OUT=MINIMUM// and the value has to be decreased, it is set to MAXIMUM and counts down.
  * //BRING=FALSE//: If //OUT=MAXIMUM// and the value has to be increased, no operation is done (the value stops at MAXIMUM). If //OUT=MINIMUM// and the value has to be decreased, the value stops at MINIMUM.

The counter may be reset by a rising edge at the //BR// input. If //BR=TRUE// then //OUT=MINIMUM// and counting is stopped.

===== Inputs =====

|Input  |Type|Description                                                                                                                                             |Default value|
|BX     |BOOL|Rising edge increases the //OUT// value by 1                                                                                                            |False        |
|BXF    |BOOL|Falling edge increases the //OUT// value by 1                                                                                                           |False        |
|BXD    |BOOL|Rising edge decreases the //OUT// value by 1                                                                                                            |False        |
|BXDF   |BOOL|Falling edge decreases the //OUT// value by 1                                                                                                           |False        |
|BR     |BOOL|Reset – if //BR=TRUE// then //OUT=MINIMUM//                                                                                                             |False        |
|MINIMUM|LINT|Minimum value of //OUT//                                                                                                                                |0            |
|MAXIMUM|LINT|Maximum value of //OUT//                                                                                                                                |10000        |
|BRING  |BOOL|Overflow switch. If //BRING=TRUE// then the counter is a cyclic counter, if //BRING=FALSE// then the counter stops at //MINIMUM// or //MAXIMUM// values.|False        |

===== Outputs =====

|Output|Type|Description                                                                                  |
|OUT   |LINT|Counter value (//OUT// may be equal to //MINIMUM,MINIMUM+1,MINIMUM+2,...,MAXIMUM-1,MAXIMUM//)|

===== Application example =====

{{:en:mervis-ide:35-help:bd30_example.png}}\\


The counter counts pulses generated by the BD2 block. Each rising edge increases the counter by 1. The counter is used to count events or to control a cascade heating plant.