[ Node-RED ] Komunikasi Dengan Perangkat MODBUS-RTU Serial - Praktek Sensor Suhu + 7 Segmen

 

Modbus dan PLC  baik dalam komunikasi jadulnya yg berbasis serial RS 485/ RS 232 maupun kini sudah merambah ke komunikasi TCP/IP, menjadi pilihan yang menurut penulis sudah "Final" dikalangan dunia kontrol industrial. Pengalaman penulis ketika menawarkan otomasi berbasis mikrokontroller 8 bit yg saya rancang dengan fungsi yang hampir sama, tetap mendapatkan tantangan dan pertanyaan seputar kehandalannya. Jadi saya yang pecinta hardware dasar pun di sangsikan apalagi mereka yg ingin menawarkan kemudahan dari sisi dunia IT. Sehingga menurut rekan dosen otomasi di UK-Petra Surabaya, Node-Red menjadi jembatan yang ampuh untuk menyatukan perangkat jadul dengan sistem IOT-Industri 4.0

Seperti yang pernah saya bahas di tahun sebelumnya, saat saya belajar dan berhasil merancang Modbus-RTU bridging ke MQTT (silahkan mulai disini , dibaca dan dipahami terlebih dahulu), mutlak diperlukan pemahaman sistem pengiriman data, register I/O , error checking dan sebagainya. Untuk itu perlu diulang kembali praktek awal belajar modbus yaitu menjadikan arduino sebagai perangkat Modbus-slave, dengan penyesuaian rangkaian yg sudah saya buat di praktek node-red sebelumnya,  sebagai berikut :

Dengan Input berupa pembacaan suhu dan kelembaban, maka saya menempatkan data pada Input / Analog Register berupa :

• 30001 : Angka didepan koma / Puluhan suhu
• 30002 : Angka desimal / di belekang koma suhu
• 30003 : Angka pengukukuran kelembaban

Sedangkan untuk Output berupa 7 segmen, register yg digunakan adalah Holding Register dengan alamat 40001. Register ini juga dapat diubah mengunakan Function 0x06. Jadi script untuk merubah rangkaian arduino diatas menjadi berbasis MODBUS-RTU sebagai berikut :

//Silahkan unduh Library modbus slave: 
//https://code.google.com/archive/p/arduino-modbus-slave/downloads

#include <modbus.h>
#include <modbusDevice.h>
#include <modbusRegBank.h>
#include <modbusSlave.h>
#include "DHT.h"

//7seg

#define SEGA 5
#define SEGB 6
#define SEGC 7
#define SEGD 8
#define SEGE 9
#define SEGF 10
#define SEGG 11

#define dhtPin 4
#define DHTTYPE DHT22
DHT dht(dhtPin, DHTTYPE);

unsigned long previousMillis = 0;
const long interval = 5000; 


modbusDevice regBank;
modbusSlave slave;

void setup()
{   //7 seg
    pinMode(SEGA, OUTPUT);
    pinMode(SEGB, OUTPUT);
    pinMode(SEGC, OUTPUT);
    pinMode(SEGD, OUTPUT);
    pinMode(SEGE, OUTPUT);
    pinMode(SEGF, OUTPUT);
    pinMode(SEGG, OUTPUT);

 //Ubah modbus device ID.  
  regBank.setId(6);
  dht.begin();
/*
register modbus mengikuti format berikut
00001-09999 Output Digital, Perangkat master dapat membaca dan menulis ke register ini
10001-19999 Input Digital, Perangkat master hanya dapat membaca nilai dari register ini
30001-39999 Input Analog, Perangkat master hanya dapat membaca nilai dari register ini
40001-49999 Output Analog/ Holding register, 
            Perangkat master dapat membaca dan menulis ke register ini

Nilai analog adalah kata unsigned 16 bit yang disimpan dengan kisaran 0-32767
Nilai digital disimpan sebagai byte, nilai nol OFF dan nilai nonzer ON

Cara terbaik adalah mengkonfigurasi register tipe serupa ke dalam blok yang bersebelahan. ini
memungkinkan pencarian register yang lebih efisien dan dan mengurangi jumlah pesan
dibutuhkan oleh master untuk mengambil data
*/

 
//Pesan alamat Register Analog input di register bank 30001-10010 
  regBank.add(30001);  //DHT11 - suhu puluhan
  regBank.add(30002);  //DHT11 - suhu desimal
  regBank.add(30003);  //DHT11 - kelembaban
  
//Pesan alamat Holding Register 40001
  regBank.add(40001);  // 7 SEGMEN
//Isi nilai awal dari 7 segmen
  regBank.set(40001,8);
    

  slave._device = &regBank;  

// Serial 9600 baud  
  slave.setBaud(9600);   

}

void segmen(int angka)
{
 
   switch(angka) {
                  case 0 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, HIGH);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, LOW);
                             break;
                  }
                  case 1 : { digitalWrite(SEGA, LOW);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, LOW);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, LOW);
                             digitalWrite(SEGG, LOW);
                             break;
                  }
                  case 2 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, LOW);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, HIGH);
                             digitalWrite(SEGF, LOW);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }
                  case 3 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, LOW);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }
                  case 4 : { digitalWrite(SEGA, LOW);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, LOW);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }

                  case 5 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, LOW);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }                                                          
                  case 6 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, LOW);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, HIGH);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }
                  case 7 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, LOW);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, LOW);
                             digitalWrite(SEGG, LOW);
                             break;
                  }
                  case 8 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, HIGH);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }
                  case 9 : { digitalWrite(SEGA, HIGH);
                             digitalWrite(SEGB, HIGH);
                             digitalWrite(SEGC, HIGH);
                             digitalWrite(SEGD, HIGH);                             
                             digitalWrite(SEGE, LOW);
                             digitalWrite(SEGF, HIGH);
                             digitalWrite(SEGG, HIGH);
                             break;
                  }
   }
}

// mengubah koma 
int ExtractDecimalPart(float Value, int numberOfDecimals)
{
  float temp = Value - (long)(Value); 
  long p = 1;
  for (int i=0; i< numberOfDecimals; i++) p*=10;
  long DecimalPart = p * temp;
  return DecimalPart;
}

void loop()
{
//Tulis 7 segmen sesuai nilai pada register
  segmen(regBank.get(40001));  


//Baca suhu 5 detikan
  unsigned long currentMillis = millis();
 
  if(currentMillis - previousMillis >= interval) {
   
    previousMillis = currentMillis;   
 
    int h = dht.readHumidity();
    float t= dht.readTemperature();
    int t1 = t;
    int t2 = ExtractDecimalPart(t,2);

//tulis ke register 30001 -30003
    if (isnan(h) || isnan(t)) {
    regBank.set(30001,1000);
    regBank.set(30002,1000);
    regBank.set(30003,1000); 
    }

    
    regBank.set(30001,t1);
    regBank.set(30002,t2);
    regBank.set(30003,h);
   } 

  //jalan terus berulang sebagai slave  
  slave.run();  

}

Jadi jika selesai programming, dapat dilakukan test dengan software simulator modbus RADZIO : 

7 segmen kemudian bisa juga diubah dengan klik 2x pada kolom register  yang sesuai .

Selanjutnya di sisi Node-RED kita akan melakukan instalasi node yg bernama node-red-contrib-modbus. Instalasinya bisa juga dilakukan melalui editor Node-RED dengan memilih pilihan "manage pallete" di menu kanan atas.

Dengan demikian kita bisa menggunakan NODE modbus paling dasar yaitu MODBUS READ untuk membaca sensor suhu kelembaban DHT22 yg saya pakai. Settingnya cukup menyesuaikan dengan praktek sebelumnya yaitu penyesuaian com port, ID slave, dan debug sebagai output.

Hasilnya mencengangkan !

Sehari-semalam saya bingung dibuatnya, kenapa response dari Modbus Slave menampilkan array [0,0,0] ? Sampai kemudian saya ingat ada tools untuk melakukan debug / spy serial port bernama " SerialMon".

Dari hasil penelusuran, saya bandingkan serial yg dikirim terima oleh Radzio dengan Node-RED dan hasilnya saya salah di penomeran register.

Kejadian lagi deh kesalahan saat awal belajar modbus dulu ...jadi alamat register bukan dimulai dari 30001 melainkan cukup ditulis 0 (karena aturan offset jadi 1), ingat deh dulu seperti ini nih seharusnya :

06 04 00 00 00 03 B1 BC

06     =  Alamat device id slave

04     =  Perintah baca input analog/ function 04

00 00  = 2 byte alamat address memori (mulai 0 , logic 1)

00 03  = 2 byte panjang data yg diharapkan (3 buah data)

B1 BC  = Checksum / CRC 16 modbus

Dan yang benar seperti ini nih...langsung muncul angka suhu dan kelembabanya ...

 

Selanjutnya praktek sangat lancar dan cukup mengikuti praktek Node-RED web UI sebelumnya dan berhasil membuat hasil seperti video berikut ini :

Untuk Script Node-Red dalam JSON, saya tempel aja disini, kemudian bisa di import dan copy paste pada editor Node-RED kamu :

[{"id":"a8d0e1d9.32142","type":"tab","label":"Flow 5","disabled":false,"info":""},{"id":"d299086b.f08a88","type":"modbus-read","z":"a8d0e1d9.32142","name":"","topic":"","showStatusActivities":false,"logIOActivities":false,"showErrors":false,"unitid":"6","dataType":"InputRegister","adr":"0","quantity":"3","rate":"5","rateUnit":"s","delayOnStart":false,"startDelayTime":"","server":"824b1538.161228","useIOFile":false,"ioFile":"","useIOForPayload":false,"emptyMsgOnFail":false,"x":279.32994079589844,"y":205.96183681488037,"wires":[["7967f3c9.3415bc","5cfa62af.b1f89c","e0c9cab0.13e948"],[]]},{"id":"7967f3c9.3415bc","type":"debug","z":"a8d0e1d9.32142","name":"read_modbus","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":526.3299407958984,"y":55.16672134399414,"wires":[]},{"id":"341bb8e1.0d3b38","type":"modbus-write","z":"a8d0e1d9.32142","name":"","showStatusActivities":false,"showErrors":false,"unitid":"6","dataType":"HoldingRegister","adr":"0","quantity":"1","server":"824b1538.161228","emptyMsgOnFail":false,"keepMsgProperties":false,"x":685.3369064331055,"y":450.8092050552368,"wires":[[],[]]},{"id":"b0f6eeca.9fc8f","type":"debug","z":"a8d0e1d9.32142","name":"out_modbus","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":681.3334045410156,"y":365.1701936721802,"wires":[]},{"id":"36302ceb.d3b7b4","type":"inject","z":"a8d0e1d9.32142","name":"decrement","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":"","topic":"","payload":"2","payloadType":"num","x":272.8958435058594,"y":403.8888854980469,"wires":[["44bf1fc9.8d7fd"]]},{"id":"96e67c14.b9386","type":"inject","z":"a8d0e1d9.32142","name":"increment","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":"","topic":"","payload":"1","payloadType":"num","x":272.8958435058594,"y":363.8888854980469,"wires":[["44bf1fc9.8d7fd"]]},{"id":"44bf1fc9.8d7fd","type":"function","z":"a8d0e1d9.32142","name":"7 segmen","func":"var count=flow.get('count') || 0;\n\nvar temp = msg.payload\n\nif(temp == 1) count+=1;\nelse if(temp == 2) count-=1;\n\nif(count > 9) count =0;\nif(count < 0) count =9;\n\nflow.set('count',count);\n\nvar result = {payload:count};\nreturn[result];","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":473.89587783813477,"y":379.8889045715332,"wires":[["b0f6eeca.9fc8f","341bb8e1.0d3b38","8ca591c3.507c8"]]},{"id":"39680ef0.a0ec02","type":"ui_gauge","z":"a8d0e1d9.32142","name":"SUHU DHT 11","group":"fc14d827.fe2ea8","order":1,"width":0,"height":0,"gtype":"gage","title":"Suhu Celcius","label":"Celcius","format":"{{value}}","min":0,"max":"50","colors":["#00b500","#e6e600","#ca3838"],"seg1":"","seg2":"","x":746.8958358764648,"y":147.88887405395508,"wires":[]},{"id":"fc85d4ce.fbaa78","type":"ui_chart","z":"a8d0e1d9.32142","name":"","group":"fc14d827.fe2ea8","order":2,"width":0,"height":0,"label":"Kelembaban %Rh","chartType":"line","legend":"false","xformat":"HH:mm:ss","interpolate":"linear","nodata":"","dot":false,"ymin":"40","ymax":"100","removeOlder":1,"removeOlderPoints":"","removeOlderUnit":"60","cutout":0,"useOneColor":false,"useUTC":false,"colors":["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"outputs":1,"useDifferentColor":false,"x":756.8958511352539,"y":260.88890075683594,"wires":[[]]},{"id":"5cfa62af.b1f89c","type":"function","z":"a8d0e1d9.32142","name":"ubah suhu","func":"var temp = msg.payload;\nvar puluhan = temp[0]\nvar desimal = temp[1]\n\nvar ongko = (parseInt(puluhan) * 100) + desimal;\nvar suhu = parseFloat(ongko /100);\nvar result = {payload:suhu};\nreturn[result];\n","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":532.3402481079102,"y":154.70834350585938,"wires":[["39680ef0.a0ec02"]]},{"id":"e0c9cab0.13e948","type":"function","z":"a8d0e1d9.32142","name":"ubah humi","func":"var temp = msg.payload\nvar humi = parseInt( temp[2] )\n\nvar result = {payload:humi};\nreturn[result];\n","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":527.8958129882812,"y":237.88888549804688,"wires":[["fc85d4ce.fbaa78","f739dfd5.58126"]]},{"id":"f739dfd5.58126","type":"debug","z":"a8d0e1d9.32142","name":"ubah suhu","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":755.3402862548828,"y":202.18057250976562,"wires":[]},{"id":"8ca591c3.507c8","type":"ui_text","z":"a8d0e1d9.32142","group":"fc14d827.fe2ea8","order":4,"width":0,"height":0,"name":"","label":"7 Segmen","format":"{{msg.payload}}","layout":"row-spread","x":681.3299102783203,"y":407.0590515136719,"wires":[]},{"id":"5b185e1a.af2f7","type":"ui_button","z":"a8d0e1d9.32142","name":"Tambah","group":"fc14d827.fe2ea8","order":8,"width":"3","height":"2","passthru":false,"label":"Tambah ","tooltip":"","color":"","bgcolor":"","icon":"","payload":"1","payloadType":"num","topic":"payload","topicType":"msg","x":269.32643127441406,"y":313.2986240386963,"wires":[["44bf1fc9.8d7fd"]]},{"id":"a4c4a5d.a88cc58","type":"ui_button","z":"a8d0e1d9.32142","name":"Kurang","group":"fc14d827.fe2ea8","order":8,"width":"3","height":"2","passthru":false,"label":"Kurang","tooltip":"","color":"","bgcolor":"","icon":"","payload":"2","payloadType":"num","topic":"payload","topicType":"msg","x":273.8958435058594,"y":454.8888854980469,"wires":[["44bf1fc9.8d7fd"]]},{"id":"824b1538.161228","type":"modbus-client","name":"","clienttype":"simpleser","bufferCommands":true,"stateLogEnabled":false,"queueLogEnabled":false,"tcpHost":"127.0.0.1","tcpPort":"502","tcpType":"DEFAULT","serialPort":"COM7","serialType":"RTU-BUFFERD","serialBaudrate":"9600","serialDatabits":"8","serialStopbits":"1","serialParity":"none","serialConnectionDelay":"100","unit_id":"1","commandDelay":"1","clientTimeout":"1000","reconnectOnTimeout":true,"reconnectTimeout":"2000","parallelUnitIdsAllowed":true},{"id":"fc14d827.fe2ea8","type":"ui_group","name":"modbus RTU ui testing","tab":"53c1826d.1539dc","order":2,"disp":true,"width":"6","collapse":false},{"id":"53c1826d.1539dc","type":"ui_tab","name":"HumiTemp Node Red","icon":"dashboard","order":1,"disabled":false,"hidden":false}]

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