Equipments (Devices) > SCA06 > Ladder > Hardware

Block that performs counting of encoder pulses.

Ladder Representation

READENC5_block

Block Structure

Variable Type	Name	Data Type	Description
VAR_INPUT	EN	BOOL	Block enabling
	COUNT_SRC	BYTE	It determines which encoder will be used in counting of pulses
	PRESET	BOOL	Attributes value from PV to CV
	RESET#	BYTE	Chooses the CV reset control
	RESET_VAR	BOOL	If the choice of RESET # is by variable, it performs the reset of CV when in TRUE value
	SAVE#	BYTE	Chooses the saving control of the counter
	SAVE_VAR	BOOL	If the choice of SAVE# is by variable, it performs the saving of CV in SV when in TRUE value
	REF_CNT	LREAL	Value of the reference pulse for output enabling
	PV	LREAL	Value of initial configuration
	RESTART	LREAL	Reference value for automatic reset of CV
VAR_OUTPUT	Q	BOOL	Output enabling
	RESET_OCC	BOOL	Reset flag
	SAVE_OCC	BOOL	Saving flag
	CV	LREAL	Value of pulse counter
	SV	LREAL	Last saved counter value
VAR	READENC5_INST_0	READENC5	Instance of access to block structure

Operation

When this block identifies a leading edge in EN, it resets its outputs and counts the pulses from the encoder specified in COUNT_SRC while enabled. This count value is stored in CV.

The specified control in RESET# resets the counter when enabled, while the specified control in SAVE#, when activated, stores the value of CV in SV. Each of these controls sets its respective flag (RESET_OCC or SAVE_OCC) for one scan cycle.

The block also allows you to configure an automatic reset when CV reaches the RESTART value.

The value of Q is activated by one scan cycle when CV reaches the value of REF_CNT.

Block Flowchart

READENC5_flowchart

Example in Ladder

READENC5_example01

The above example reads the encoder 1 and stores its value in COUNTER, with count reference set in REF and RESET and SAVE control done by the variables LOAD_ZERO and SAVE_COUNT, respectively. When COUNTER is equals to REF, the output Q is set for one scan cycle.

Example in ST

The example below displays the instructions for applying the example above in the ST language.

VAR

LOAD_PRESET, LOAD_ZERO, SAVE_COUNT : BOOL;

REF1, PRESET_VALUE, RESTART : LREAL;

FLAG_RESET, FLAG_SAVE : BOOL;

COUNTER, COUNTER_SAVED : LREAL;

FB_READENC5_INST_0 : FB_READENC5;

END_VAR

FB_READENC5_INST_0(

EN:=DI1,

COUNT_SRC:=1,

PRESET:=LOAD_PRESET,

RESET:=0,

RESET_VAR:=LOAD_ZERO,

SAVE:=0,

SAVE_VAR:=SAVE_COUNT,

REF_CNT:=REF1,

PV:=PRESET_VALUE,

RESTART:=RESTART,

RESET_OCC=>FLAG_RESET,

SAVE_OCC=>FLAG_SAVE,

CV=>COUNTER,

SV=>COUNTER_SAVED,

Q=>DO1);