The COUNTER3 device is used to acquire information from a two-way counter. Its main characteristics:

• conversion of pulses to selected unit measures
• position updating with recovery of unit measure fractions
• position capturing on activation of an interrupt digital input
• comparison between measured position and an activation threshold of digital outputs.

To use the device it has to be declared in the INTDEVICE section of the configuration unit.

INTDEVICE
<device name> COUNTER3 <TCamp> <ICont> <IdxA> <Out1> <Out2>

Where:

Example:

INTDEVICE
Count  COUNTER3  2  2.CNT02  3    2.OUT01  2.OUT02

	All fields in the declaration are mandatory and must be on the same line. Set X.X or X if a resource is not available or not used. If a resource is disabled all the functionalities related to the device are disabled.

A block chart of the device:

The “Factors” block calculates the conversion factors for position and speed. The “position factor” (PF) is a position conversion coefficient expressed in the unit measure of the of the transducer in the position unit measure (Um), and vice versa. Usually the position unit measure is, for example, metres or millimetres or centimetres, while the transducer unit measure, as an encoder, is always pulses. The parameters used to calculate the position factor are pulse and measure and it is calculated as a ratio between the two.

The INTENBL and INTDSBL commands enable (st_intenbl=1) and disable (st_intenbl=0) the interrupt line connected to the zero pulse of the transducer or another sensor. The value of the capture parameter defines which pulse front the instant count is frozen and the count captured is introduced in the delta parameter. The st_capture status signals that the capture is made.

The device also provides two comparators that can be used to compare the actual value of the posit parameter with two values (setpoint1 and setpoint2) set by the programming. As a result the comparators act on two digital outputs, activating or disactivating them when the set thresholds are met according to various conditions. There are two outputs available (as seen in the the device declaration and block chart) and there is a good level of personalisation: each comparator can select which output to command and based on which conditions. The mode1 parameters (controlling comparator 1) selects the activation or disattivazione policy of the corresponding output according to given rules.

The figure shows examples of the different execution modes:

• mode 0: the output stays in its status
• mode 1: the output is activated when the position in pulse fronts is greater than the setpoint;
• mode 2: the output is disactivated when the position in pulse fronts is greater than the setpoint;
• mode 3: the output is activated when the position in pulse fronts is less than the setpoint;
• mode 4: the output is disactivated when the position in pulse fronts is less than the setpoint;
• mode 5: the output is activated when the position in pulse fronts is greater than the setpoint and is disactivated when the position in pulse fronts is less than the setpoint;
• mode 6: the output is disactivated when the position in pulse fronts is greater than the setpoint and is activated when the position in pulse fronts is less than the setpoint.

The device always gives the absolute position of the axis. The count change can also be performed by directly writing the new value of the posit parameter.
If 100 unit measures are subtracted from the count:

  Count.posit = Count.posit - 100

An error is introduced because it sets the position “posit = -100”, when the axis may have an intermediary position between one unit measure and the next (e.g. 100.3). This fraction (0.3) is lost and if repeated can cause a build up of a significant error.
For this reason there is the DELCNT command that can change the posit by a value set by the delta parameter.
For instance, if pulse and measure are configured to express the position in tenths of a degree and posit expresses the angular position. For this to always fall between zero and 360 degrees, the following code must be added:

  IF Count.posit GE 3600
    Count.delcnt = -3600
    Count.DELCNT
  ENDIF  

For the command execution conditions see its specific description. Execution of the DELCNT command is ensured even if a unit measure cannot be expressed as a finite number of pulse fronts. For instance with parameters measure = 1000 and pulse = 1024, the value 3600 of the previous example corresponds to 3686.4 pulses. A complex internal algorhythm allows the device to consider the decimal part of this value and by internal accumulators, it becomes part of the information used to change the posit value.
Example:
If pulse = 10, measure = 1, the axis position reading is 2 and it is found at point A.

To add two unit measures to the posit position. The instructions :

  Count.posit = Count.posit + 2

take the axis to the new position B. The instructions:

  Count.delta = 2
  Count.DELCNT Asse

take the axis to position C.

If posit is modified directly without using the DELCNT command (as in the first example) an error is introduced.

	To send a sequence of DELCNT commands, it is best to calculate the size of the addition and only send the command once. If this is not possible great care must be taken to avoid sending a sequence of commands not separated by a read instruction on the device parameter. Example: Count.delta = 3 Count.DELCNT WAIT Count.delta Count.delta = 40 Count.DELCNT

The presence of an error in device is reported in the state st_error.
When st_error is equal to 1, we find in the variable errcode the type of error intervened (see table) and in the variable errvalue an indication of the cause of the error.
If the device is in error, to resume production you need to erase the state through the command RSERR

The presence of a warning in device is reported in the state st_warning.
When st_warning is equal to 1, we find in the variable wrncode the type of warning intervened (see table) and in the variable wrnvalue an indication of the cause of the warning.

To clear the status st_warning we must send the command RSWRN.

—-

The commands provided to manage the device are listed below, ordered in decreasing priority. There are two ways to execute a command: * By the Qview watches panels * By a QCL instruction

In the second case the QCL program execution is blocked until the end of the command, which lasts between 0 and 2 sampling times.

If you change the parameters measure or pulse after sending the command DELCNT, the remains of the conversion of the delta space in pulses are reset.

;*************************************************************************************
; COUNTER3 example
;*************************************************************************************
 
; Bus declaration
BUS
  1  1K31F    20
  2  .        .
  3  1MG8F    .
  4  .
 
; Input declaration
INPUT
  ifEnableZ     F     3.INP01        ;Zero pulse capture enabling
  ifEnableComp  F     3.INP03        ;Comparation enabling
 
; Output declaration
OUTPUT
  out201      F     3.OUT01        ;Comparation output #1
  out202      F     3.OUT02        ;Comparation output #2 
 
; Device declaration
INTDEVICE
Count    COUNTER3   2       3.CNT01     1       3.OUT01  3.OUT02
 
END

SYSTEM
  slPrsPos   L  IN               ;Quota di preset
  slSet1     L  IN               ;Setpoint 1
  slSet2     L  IN               ;Setpoint 2
 
GLOBAL
  gfApp01    F
  gfApp02    F
 
BEGIN
;-------------------------------------------------------------------------------------
; Initialization
;-------------------------------------------------------------------------------------
Count.measure = 1000             ;measure per round
Count.pulse = 1000               ;pulse per round
 
Count.capture = 1                ;set capture on rise edge
IF slSet1 EQ 0
  slSet1 = 500                   ;Default value 
ENDIF
IF slSet2 EQ 0
  slSet2 = 100                   ;Default value
ENDIF
 
MAIN:
 
 
  IF ifEnableZ                                 ;If the input is ON
    Count.INTENBL                              ;Zero pulse enabling
  ELSE
    Count.INTDSBL                              ;Zero pulse disabling
  ENDIF
 
  IF Count.st_capture                          ;When the count has captured
    Count.delta = -(Count.delta - slPrsPos)    ;load delta
    Count.DELCNT                               ;Set the new position
    Count.RSCAPTURE                            ;Reset the capture
  ENDIF
 
  IF ifEnableComp                              ;When it is enabled
    IF NOT gfApp01
      Count.mode1 = 5                           ;Set Mode1 for comparation 1
      Count.selout1 = 0                         
      Count.setpoint1 = slSet1
      Count.timer1 = 0
      Count.mode2 = 6                           ;Set Mode2 for comparation 2
      Count.selout2 = 1                         
      Count.setpoint2 = slSet2
      Count.timer2 = 0
      gfApp01 = 1
      gfApp02 = 0
    ENDIF
  ELSE                                         ;When it is not enabled
    IF NOT gfApp02
      Count.mode1 = 0                           ;Comparation 1 disabled
      RESOUT out201                            ;Reset output
      Count.selout1 = 0
      Count.mode2 = 0                           ;Comparation 1 disabled  
      RESOUT out202                            ;Reset output
      Count.selout2 = 1
      gfApp01 = 0
      gfApp02 = 1
    ENDIF
  ENDIF
 
  WAIT 1
  JUMP MAIN
 
END