How to Use Incremental Encoders

1/*
2 *  Application note: incremental encoder and RS422/RS485 Shield  
3 *  Version 1.0
4 *  Copyright (C) 2020  Hartmut Wendt  www.zihatec.de
5  *  
6 *  used encoder: SICK DFS60 www.sick.com
7 *  
8 *
9 *  This program  is free software: you can redistribute it and/or modify
10 *  it under the terms  of the GNU General Public License as published by
11 *  the Free Software Foundation,  either version 3 of the License, or
12 *  (at your option) any later version.
13  *
14 *  This program is distributed in the hope that it will be useful,
15 *  but  WITHOUT ANY WARRANTY; without even the implied warranty of
16 *  MERCHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *  GNU General Public License  for more details.
18 *
19 *  You should have received a copy of the GNU General  Public License
20 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
21*/   
22
23
24// Pin definitions
25const byte ZeroPin = 2;  // RS422 input for  Z channel (zero detection)
26const byte COSPin = 3;   // RS422 input for A channel  (cos signal) 
27const byte SINPin = 4;   // RS422 input for B channel (sin signal)  
28
29// variables
30enum {ENC_STOP, ENC_CLOCKWISE_ROTATION, ENC_COUNTERCLOCKWISE_ROTATION};  // encoder operation modes
31volatile byte encoder_state = ENC_STOP;
32volatile  int encoder_position = 0; 
33volatile int encoder_oldpos = 0; 
34
35
36
37void  setup() {
38  Serial.begin(115200); //Use serial monitor for debugging
39
40  // Define pins for input and output
41  pinMode(SINPin, INPUT);
42
43  // set  internal pullup resistor for interrupt pin
44  pinMode(COSPin, INPUT_PULLUP);
45  pinMode(ZeroPin, INPUT_PULLUP);
46  
47  
48  // set 1st interrupt service  routine to COSPin and 'RISING' edge 
49  attachInterrupt(digitalPinToInterrupt(COSPin),  encoder_isr, RISING);
50
51  // set 2nd interrupt service routine to ZeroPin and  'HIGH' level 
52  attachInterrupt(digitalPinToInterrupt(ZeroPin), zero_detection_isr,  HIGH);
53}
54
55
56void loop() {
57  // Detect Encoder Stop
58  if (encoder_oldpos  == encoder_position) encoder_state= ENC_STOP;
59
60  // output encoder incremental  and status
61  Serial.print("Encoder position: ");
62  Serial.print(encoder_position);
63  Serial.print(", Encoder state: ");
64  
65  if (encoder_state==ENC_CLOCKWISE_ROTATION)  {
66    Serial.println("Clockwise Rotation");
67        
68  } else if (encoder_state==ENC_COUNTERCLOCKWISE_ROTATION)  {
69    Serial.println("Counter-Clockwise Rotation");
70    
71  } else {
72    Serial.println("Stop");  
73  }
74  
75  encoder_oldpos = encoder_position;
76  
77  delay(500);
78}
79
80
81void encoder_isr() {
82  
83  if  (digitalRead(SINPin)  == LOW) {
84    // clockwise rotation
85    encoder_state=ENC_CLOCKWISE_ROTATION;
86    encoder_position++;
87  } else {
88    //counter-clockwise rotation
89    encoder_state=ENC_COUNTERCLOCKWISE_ROTATION;
90    encoder_position--;    
91  } 
92}
93
94
95void zero_detection_isr() {
96  // detect pulse on zero channel
97  encoder_position = 0;
98}

1/*
2 *  Application note: incremental encoder and RS422/RS485 Shield   
3 *  Version 1.0
4 *  Copyright (C) 2020  Hartmut Wendt  www.zihatec.de
5   *  
6 *  used encoder: SICK DFS60 www.sick.com
7 *  
8 *
9 *  This program   is free software: you can redistribute it and/or modify
10 *  it under the terms   of the GNU General Public License as published by
11 *  the Free Software Foundation,   either version 3 of the License, or
12 *  (at your option) any later version.
13   *
14 *  This program is distributed in the hope that it will be useful,
15 *  but   WITHOUT ANY WARRANTY; without even the implied warranty of
16 *  MERCHANTABILITY   or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *  GNU General Public License   for more details.
18 *
19 *  You should have received a copy of the GNU General   Public License
20 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
21*/    
22
23
24// Pin definitions
25const byte ZeroPin = 2;  // RS422 input for   Z channel (zero detection)
26const byte COSPin = 3;   // RS422 input for A channel   (cos signal) 
27const byte SINPin = 4;   // RS422 input for B channel (sin signal)   
28
29// variables
30enum {ENC_STOP, ENC_CLOCKWISE_ROTATION, ENC_COUNTERCLOCKWISE_ROTATION};   // encoder operation modes
31volatile byte encoder_state = ENC_STOP;
32volatile   int encoder_position = 0; 
33volatile int encoder_oldpos = 0; 
34
35
36
37void   setup() {
38  Serial.begin(115200); //Use serial monitor for debugging
39
40   // Define pins for input and output
41  pinMode(SINPin, INPUT);
42
43  // set   internal pullup resistor for interrupt pin
44  pinMode(COSPin, INPUT_PULLUP);
45   pinMode(ZeroPin, INPUT_PULLUP);
46  
47  
48  // set 1st interrupt service   routine to COSPin and 'RISING' edge 
49  attachInterrupt(digitalPinToInterrupt(COSPin),   encoder_isr, RISING);
50
51  // set 2nd interrupt service routine to ZeroPin and   'HIGH' level 
52  attachInterrupt(digitalPinToInterrupt(ZeroPin), zero_detection_isr,   HIGH);
53}
54
55
56void loop() {
57  // Detect Encoder Stop
58  if (encoder_oldpos   == encoder_position) encoder_state= ENC_STOP;
59
60  // output encoder incremental   and status
61  Serial.print("Encoder position: ");
62  Serial.print(encoder_position);
63   Serial.print(", Encoder state: ");
64  
65  if (encoder_state==ENC_CLOCKWISE_ROTATION)   {
66    Serial.println("Clockwise Rotation");
67        
68  } else if (encoder_state==ENC_COUNTERCLOCKWISE_ROTATION)   {
69    Serial.println("Counter-Clockwise Rotation");
70    
71  } else {
72     Serial.println("Stop");  
73  }
74  
75  encoder_oldpos = encoder_position;
76   
77  delay(500);
78}
79
80
81void encoder_isr() {
82  
83  if  (digitalRead(SINPin)   == LOW) {
84    // clockwise rotation
85    encoder_state=ENC_CLOCKWISE_ROTATION;
86     encoder_position++;
87  } else {
88    //counter-clockwise rotation
89    encoder_state=ENC_COUNTERCLOCKWISE_ROTATION;
90     encoder_position--;    
91  } 
92}
93
94
95void zero_detection_isr() {
96   // detect pulse on zero channel
97  encoder_position = 0;
98}