#CCS C MODBUS RTU HOW TO#
#CCS C MODBUS RTU DRIVER#
#CCS C MODBUS RTU CODE#

Then after you have called _one_ read_holding_registers operation, Then you need to call 'modbus_init' before trying to use the modbus

#CCS C MODBUS RTU DRIVER#

You are also not telling the modbus driver what protocol to support However, the best way to figure it out is to play with the code, starting with printing your values as shown by the CCS example code, and then moving on to storing it in your own data structures and so on. So in your function, you will need to swap element 0 with element 1, element 2 with element 3, and so on and so forth. But ALSO, keep in mind that while it prints fine if you are doing it like the CCS example, the bytes are swapped when you store them in array. I used the union data structure to conveniently access this. Keep in mind that this modbus_rx.data is an array of int8's, and each register is 16-bits so each pair of bytes that you read is one element of data. Instead of printing the data, I modified that line to place each element in the modbus_rx.data array. Pointer to array where I can store the data I modified that function so that I can input as parameters: When you open ex_modbus_master.c, do a search for read_all_holding(). Then, you need to initialize the modbus driver using modbus_init().

#CCS C MODBUS RTU CODE#

You should write some code to blink LED at 1 Hz to confirm that you have done your clock setups correctly. The first thing you have to do is make sure you have the right baud rate.

#CCS C MODBUS RTU HOW TO#

I don't have the CCS compiler on this computer, but ex_modbus_master.c has some wrapper functions with examples on how to use the modbus functions included in the library. Check ex_modbus_master.c to learn how to configure the driver to use RS485. Then, you need to wire two of your GPIO pins to the DE and RE pins, and specify that. That is incorrect! They need to be wired to the RO and DI pins (I believe it should be TX -> DI and RX -> RO). Ler = modbus_read_holding_registers(0x01,0x05,0x01) //lendo os registradores de retenГ§ГЈoДiagram: edited by JosГ© Aparecido on Tue 10:36 am edited 3 times in totalД®DIT!!!: Before you do any of this, I just noticed that you have wired your UART pins to the MAX485's receiver enable and data enable pins. #define MODBUS_SLAVE_ADDRESS 0x01 //define o endereГ§o do escravo #define MODBUS_SERIAL_ENABLE_PIN PIN_C7 //pino DE RS-485 #define MODBUS_SERIAL_RX_ENABLE PIN_C6 //pino RE RS-485 #define MODBUS_SERIAL_INT_SOURCE MODBUS_INT_EXT #fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, PUT

Update: I created a variable type int and said that it would equal the read value of the register, then that variable would be displayed on the LCD display, but I always get the value 12, does anyone know what I am doing wrong? Modbus_read_holding_registers (0x01,0x05,0x01) //read the slave retention registers at address 1 read register 5 and only 1 registerД«ut I'm not sure how to display the reading result on the display, could anyone please help me? Any missing detail I answer. So, if I just want to read the frequency value for example, I convert 0005 (frequency parameter) to hexadecimal and it stays: Modbus_read_holding_registers (address of the slave, address of the initial registrar, number of registers to read) ДЇunction 3 is used to read the retention registers. I know to read some register I should use the command from function 3: The CFW500 uses parameters, each parameter corresponds to a register that stores some data, for example: I've already started programming in CCS, I'm using just two libraries, the standard CCS LCD library and the MODBUS library.

The crystal of the microcontroller will be 20MHz. I will use a MAX485 transceiver (although the model of the diagram is the MAX487) for the communication medium. I'll attach a diagram of how the physical part will look. I'm programming in C language and using the PIC C Compiler (CCS). I need the PIC18F4550 to read some Variable Speed Drive holding registers. Hi! I'm developing a project in which I have two devices:Дў. (Help Me!) MODBUS RTU RS-485 Master-Slave Send them to Me!) MODBUS RTU RS-485 Master-Slave Please do not post bug Reports on this forum. CCS :: View topic - (Help Me!) MODBUS RTU RS-485 Master-SlaveДЇAQ Forum Help Official CCS Support Search Register Profile Log in to check your private messages Log inД¬CS does not monitor this forum on a regular basis.

Ccs c modbus rtu