Help with multiple coils/inputs

[marcusjelsch]

Hi!

1. All thumbs up for this great work.

Now my problem, how to modify the code for use with multiple coils.

Here my code:

`/*

I2C Adressen:

0x20 - Relais 0x21 - Eingänge (5 Taster und 3 Extern) 0x22 - LCD 4x20 Zeichen

*/

include

include

include

include

include

include

LiquidCrystal_I2C lcd(0x22, 4, 5, 6, 0, 1, 2, 3, 7, POSITIVE); // Set the LCD I2C address

ModbusIP mb; //PCF8574 Objekt PCF8574 inputs; // PCF8574 mit Adresse 0x21 PCF8574 outputs; // PCF8574 mit Adresse 0x20

void setup() { // The media access control (ethernet hardware) address for the shield byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // The IP address for the shield byte ip[] = { 192, 168, 0, 44 }; //Config Modbus IP mb.config(mac, ip);

for (int i=100;i<8;i++) { mb.addIsts(i); }

for (int i=200;i<8;i++) { mb.addCoil(i); }

io_setup(); // Eingänge und Ausgänge initialisieren

lcd.begin(20,4);
}

void loop() { // poll messages mb.task();

lcd.home (); lcd.print ("Adr.: 192.168.0.44:502"); lcd.print (" ");

// link the Arduino pins to the Modbus array io_poll(); }

void io_setup() {
inputs.begin(0x21); for (int i=0;i<8;i++) { inputs.pinMode(i, INPUT_PULLUP); }

outputs.begin(0x20); for (int i=0;i<8;i++) { outputs.pinMode(i, OUTPUT); } }

/**

• Link between the Arduino pins and the Modbus array */ void io_poll() {

  //Digitale Eingange abfragen for (int i=100;i<8;i++) { mb.Ists(i, inputs.digitalRead( i-100 ) ); }

  //Digitale Ausgänge //Adresse 16-31 outputs.digitalWrite( 0, mb.Coil(202)); outputs.digitalWrite( 1, mb.Coil(201)); outputs.digitalWrite( 2, mb.Coil(200)); outputs.digitalWrite( 3, mb.Coil(203)); outputs.digitalWrite( 4, mb.Coil(207)); outputs.digitalWrite( 5, mb.Coil(206)); outputs.digitalWrite( 6, mb.Coil(205)); outputs.digitalWrite( 7, mb.Coil(204));

}`

I can only read the input at adress 100.

What am i doing wrong?

Thank u for help.

[marcusjelsch]

Found!

I made mistakes in the for-loops!

But now i have the problem, that at adress 107 and at adress 207 i can see/do no changes???!!!

Here my actual code:

`/*

I2C Adressen:

0x20 - Relais 0x21 - Eingänge (5 Taster und 3 Extern) 0x22 - LCD 4x20 Zeichen

*/

include

include

include

include

include

include

LiquidCrystal_I2C lcd(0x22, 4, 5, 6, 0, 1, 2, 3, 7, POSITIVE); // Set the LCD I2C address

ModbusIP mb; //PCF8574 Objekt PCF8574 inputs; // PCF8574 mit Adresse 0x21 PCF8574 outputs; // PCF8574 mit Adresse 0x20

void setup() { // The media access control (ethernet hardware) address for the shield byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // The IP address for the shield byte ip[] = { 192, 168, 0, 44 }; //Config Modbus IP mb.config(mac, ip);

for (int i=100;i<108;i++) { mb.addIsts(i); }

for (int i=200;i<208;i++) { mb.addCoil(i); }

io_setup(); // Eingänge und Ausgänge initialisieren

lcd.begin(20,4);
}

void loop() { // poll messages mb.task();

lcd.home (); lcd.print ("IP-Adr:192.168.0.44");

// link the Arduino pins to the Modbus array io_poll(); }

void io_setup() {
inputs.begin(0x21); for (int i=0;i<8;i++) { inputs.pinMode(i, INPUT_PULLUP); }

outputs.begin(0x20); for (int i=0;i<8;i++) { outputs.pinMode(i, OUTPUT); } }

/**

• Link between the Arduino pins and the Modbus array */ void io_poll() {

  //Digitale Eingange abfragen for (int i=100 ;i<108;i++) { mb.Ists(i, inputs.digitalRead( i-100 ) ); }

  //Digitale Ausgänge //Adresse 16-31 outputs.digitalWrite( 0, mb.Coil(202)); outputs.digitalWrite( 1, mb.Coil(201)); outputs.digitalWrite( 2, mb.Coil(200)); outputs.digitalWrite( 3, mb.Coil(203)); outputs.digitalWrite( 4, mb.Coil(207)); outputs.digitalWrite( 5, mb.Coil(206)); outputs.digitalWrite( 6, mb.Coil(205)); outputs.digitalWrite( 7, mb.Coil(204));

}`

[jsumm]

I imagine you've already figured out a fix for this, but what I've noticed is that for coils and discrete inputs there's a problem with every 8th coil/input when you access them using the multiple read/write MODBUS commands. If you have the bandwidth you can change from using read/write multiple coils to read/write single coils and loop over all 8 coils or you can read/write 7 or less coils at a time in multiple read/write calls.

I imagine the library has a bit shift error of some sort, because it happens on every 8th coil (if you were trying to work with 16 you'd have issues with both the 8th and 16th).

[DeTommer]

It's actually offsetted with 8. I'm using the following code (together with the PCA9555 shield): `

define _IO_CNT 16

//ModbusIP object ModbusIP mb; void setup() { // The media access control (ethernet hardware) address for the shield byte mac[] = { 0x00, 0x06, 0x59, 0x00, 0x1B, 0xE4 };
// The IP address for the shield byte ip[] = { 172, 16, 47, 10 };
//Config Modbus IP mb.config(mac, ip);

for(byte i=0;i<_IO_CNT;i++)
{
    ioport.pinMode(i, INPUT); //Set I2C GPIOs pinMode input
    mb.addIsts(i);  //add input status register according to ammount of inputs
}

mb.addIreg(IREG0);

}

void loop() { //Call once inside loop() - all magic here mb.task();

for(byte i=0;i<_IO_CNT;i++) { io = ioport.digitalRead(i); //read IO value from PCA9555 mb.Ists((i),io); //puts IO value in Input Status ioval+=(io<<i); //Shifts IO value in 16 bit Input Register }

mb.Ireg(IREG0,ioval);   

ioval=0; } ` What I see is that when I read register 0..7, I read the correct data at 0..6 & 15... Do 7 jumped to 15, the actual 15 has jumped to 23.

I know this project is presumed dead, but it would still be nice to find a solution or to help others :-). If I find anything, I will post it here

[DeTommer]

Fixed by using this file https://github.com/seydamir/modbus-arduino/blob/9e124a2ef7e6e06f5ad360691205ef0d04df92a0/libraries/Modbus/Modbus.cpp

[pawel3410]

DeTommer Could You send again this fixed file?