EmonHubTx3eInterfacer.py

import serial
import time
import Cargo
from pydispatch import dispatcher
import emonhub_coder as ehc
import emonhub_interfacer as ehi

"""class EmonHubTx3eInterfacer

Monitors the serial port for data

"""


class EmonHubTx3eInterfacer(ehi.EmonHubInterfacer):

    def __init__(self, name, com_port='', com_baud=9600):
        """Initialize interfacer

        com_port (string): path to COM port

        """

        # Initialization
        super(EmonHubTx3eInterfacer, self).__init__(name)

        # Open serial port
        self._ser = self._open_serial_port(com_port, com_baud)
        
        # Initialize RX buffer
        self._rx_buf = ''

    def close(self):
        """Close serial port"""
        
        # Close serial port
        if self._ser is not None:
            self._log.debug("Closing serial port")
            self._ser.close()

    def _open_serial_port(self, com_port, com_baud):
        """Open serial port

        com_port (string): path to COM port

        """

        #if not int(com_baud) in [75, 110, 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200]:
        #    self._log.debug("Invalid 'com_baud': " + str(com_baud) + " | Default of 9600 used")
        #    com_baud = 9600

        try:
            s = serial.Serial(com_port, com_baud, timeout=0)
            self._log.debug("Opening serial port: " + str(com_port) + " @ "+ str(com_baud) + " bits/s")
        except serial.SerialException as e:
            self._log.error(e)
            raise EmonHubInterfacerInitError('Could not open COM port %s' %
                                           com_port)
        else:
            return s

    def read(self):
        """Read data from serial port and process if complete line received.

        Return data as a list: [val1, val2,...]
        
        """

        # Read serial RX
        self._rx_buf = self._rx_buf + self._ser.readline()
        
        # If line incomplete, exit
        if '\r\n' not in self._rx_buf:
            return

        # Remove CR,LF
        f = self._rx_buf[:-2].strip()

        # Create a Payload object
        c = Cargo.new_cargo(rawdata=f)

        # Reset buffer
        self._rx_buf = ''

        # Parse the ESP format string
        payload=[]
        if f.startswith('ct1:'):
          for item in f.split(',')[:]:
            payload.append(item.split(':')[1])
        f=payload

        if int(self._settings['nodeoffset']):
            c.nodeid = int(self._settings['nodeoffset'])
            c.realdata = f
        else:
            if len(f)>0:
                c.nodeid = int(f[0])
                c.realdata = f[1:]

        return c