在使用modbusmaster库时定义读写功能码的例程
时间: 2024-05-08 22:14:58 浏览: 17
下面是一个使用modbusmaster库的示例程序,其中定义了读写功能码:
```
#include <ModbusMaster.h>
// Define the Modbus slave ID
#define SLAVE_ID 1
// Define the Modbus read and write function codes
#define READ_FUNC_CODE 3
#define WRITE_FUNC_CODE 16
// Define the Modbus address to read/write
#define READ_ADDRESS 0x0000
#define WRITE_ADDRESS 0x0000
// Define the Modbus data to write
#define WRITE_DATA {0x01, 0x02, 0x03, 0x04}
// Create a ModbusMaster object
ModbusMaster node;
void setup() {
// Initialize the Modbus communication
node.begin(SLAVE_ID);
}
void loop() {
// Read data from the Modbus slave
uint8_t result = node.readHoldingRegisters(READ_ADDRESS, 2);
// Check if the read was successful
if (result == node.ku8MBSuccess) {
// Print the received data
Serial.print("Received data: ");
Serial.print(node.getResponseBuffer(0), HEX);
Serial.print(node.getResponseBuffer(1), HEX);
Serial.println();
}
// Write data to the Modbus slave
uint8_t result = node.writeMultipleRegisters(WRITE_ADDRESS, 4, WRITE_DATA);
// Check if the write was successful
if (result == node.ku8MBSuccess) {
// Print a confirmation message
Serial.println("Data written successfully.");
}
// Wait for 1 second before performing another read/write
delay(1000);
}
```
在上面的代码中,我们定义了读取和写入功能码,以及要读取和写入的Modbus地址和数据。在 `setup()` 函数中,我们初始化了 `ModbusMaster` 对象,并指定了Modbus从机的ID。在 `loop()` 函数中,我们首先读取Modbus从机的数据,然后将数据写入Modbus从机。在每次读取或写入之后,我们等待1秒钟。