weight.cpp File Reference

#include "weight.h"

Go to the source code of this file.

Functions
char *	read_weight (char *buffer, int len)
	Gets the weight from the scale. More...

Function Documentation

read_weight()

char* read_weight	(	char *	buffer = weight_buf,
		int	len = 20
	)

Gets the weight from the scale.

This function is intended for the OHAUS Defender 3000 scale. It communicates over RS232 using 5V and -5V voltage levels, which will fry your microcontroller if connected directly. You will need an RS232 line driver. This function prevents buffer overruns, but no data validation is performed.

Parameters

buffer	The string to store the data into (Default value is ok)
len	The length of the buffer. (Default value is ok)

Returns

The same buffer that was passed in, containing text read from the scale.

Definition at line 6 of file weight.cpp.

                                            {
  // Clear the buffer in case someone was messing with the cable
  int n = Serial1.available();
  while( Serial1.available() > len ){
    Serial1.readBytes(buffer, len);
  }
  if( Serial1.available() ){
    Serial1.readBytes(buffer, Serial1.available());
  }
  
  // Now request the weight
  Serial1.print("P\r\n");
  len = 1 + Serial1.readBytesUntil('\n', buffer, len-1);
  buffer[len] = 0;  // Null-terminate the string
  int start_index, value_length, i;
  // Filter out spaces and linefeed
  for( i = 0; buffer[i]; ++i){
    if( buffer[i] >= '0' )
      break;
  }
  start_index = i;
  for( ; buffer[i]; ++i){
    if( buffer[i] < '.' )
      break;
  }
  value_length = i - start_index;
 
  memmove(buffer, buffer+start_index, value_length);
  buffer[value_length] = 0; // null terminate
  return( buffer );
}