read_modbus

#include <ModbusMaster.h>
ModbusMaster node;

#define MAX485_RXD 16
#define MAX485_TXD 17
const byte addr_pm = 1;

unsigned long cur_time, old_time;
float van, vbn, vcn;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial1.begin(9600, SERIAL_8N1, MAX485_RXD, MAX485_TXD);
  node.begin(addr_pm, Serial1);
}

void loop() {
  // put your main code here, to run repeatedly:
  cur_time = millis();
  if (cur_time - old_time >= 1000) {
    uint8_t result;
    uint32_t tempdouble;

    result = node.readHoldingRegisters(3027, 6);
    if (result == node.ku8MBSuccess)
    {
      tempdouble = node.getResponseBuffer(1);
      tempdouble |= node.getResponseBuffer(0) << 16;
      van = *(float*)&tempdouble;

      tempdouble = node.getResponseBuffer(3);
      tempdouble |= node.getResponseBuffer(2) << 16;
      vbn = *(float*)&tempdouble;

      tempdouble = node.getResponseBuffer(5);
      tempdouble |= node.getResponseBuffer(4) << 16;
      vcn = *(float*)&tempdouble;

      Serial.print("van: "); Serial.print(van); Serial.print(", ");
      Serial.print("vbn: "); Serial.print(vbn); Serial.print(", ");
      Serial.print("vcn: "); Serial.print(vcn);
      Serial.println();
    } else {
      Serial.println("failed read");
    }

    old_time = millis();
  }
}