enmon.py

#!/usr/bin/env python3 
#coding=utf-8

import serial
import time
import struct

class BTPOWER:

	setAddrBytes 		=	[0xB4,0xC0,0xA8,0x01,0x01,0x00,0x1E]
	readVoltageBytes 	= 	[0xB0,0xC0,0xA8,0x01,0x01,0x00,0x1A]
	readCurrentBytes 	= 	[0XB1,0xC0,0xA8,0x01,0x01,0x00,0x1B]
	readPowerBytes 		= 	[0XB2,0xC0,0xA8,0x01,0x01,0x00,0x1C]
	readRegPowerBytes 	= 	[0XB3,0xC0,0xA8,0x01,0x01,0x00,0x1D]

	def __init__(self, com="/dev/ttyUSB0", timeout=10.0):
		self.ser = serial.Serial(
			port=com,
			baudrate=9600,
			parity=serial.PARITY_NONE,
			stopbits=serial.STOPBITS_ONE,
			bytesize=serial.EIGHTBITS,
			timeout = timeout
		)
		if self.ser.isOpen():
			self.ser.close()
		self.ser.open()

	def checkChecksum(self, _tuple):
		_list = list(_tuple)
		_checksum = _list[-1]
		_list.pop()
		_sum = sum(_list)
		if _checksum == _sum%256:
			return True
		else:
			raise Exception("Wrong checksum")
			
	def isReady(self):
		self.ser.write(serial.to_bytes(self.setAddrBytes))
		rcv = self.ser.read(7)
		if len(rcv) == 7:
			unpacked = struct.unpack("!7B", rcv)
			if(self.checkChecksum(unpacked)):
				return True
		else:
			raise serial.SerialTimeoutException("Timeout setting address")

	def readVoltage(self):
		self.ser.write(serial.to_bytes(self.readVoltageBytes))
		rcv = self.ser.read(7)
		if len(rcv) == 7:
			unpacked = struct.unpack("!7B", rcv)
			if(self.checkChecksum(unpacked)):
				tension = unpacked[2]+unpacked[3]/10.0
				return tension
		else:
			raise serial.SerialTimeoutException("Timeout reading tension")

	def readCurrent(self):
		self.ser.write(serial.to_bytes(self.readCurrentBytes))
		rcv = self.ser.read(7)
		if len(rcv) == 7:
			unpacked = struct.unpack("!7B", rcv)
			if(self.checkChecksum(unpacked)):
				current = unpacked[2]+unpacked[3]/100.0
				return current
		else:
			raise serial.SerialTimeoutException("Timeout reading current")

	def readPower(self):
		self.ser.write(serial.to_bytes(self.readPowerBytes))
		rcv = self.ser.read(7)
		if len(rcv) == 7:
			unpacked = struct.unpack("!7B", rcv)
			if(self.checkChecksum(unpacked)):
				power = unpacked[1]*256+unpacked[2]
				return power
		else:
			raise serial.SerialTimeoutException("Timeout reading power")

	def readRegPower(self):
		self.ser.write(serial.to_bytes(self.readRegPowerBytes))
		rcv = self.ser.read(7)
		if len(rcv) == 7:
			unpacked = struct.unpack("!7B", rcv)
			if(self.checkChecksum(unpacked)):
				regPower = unpacked[1]*256*256+unpacked[2]*256+unpacked[3]
				return regPower
		else:
			raise serial.SerialTimeoutException("Timeout reading registered power")

	def readAll(self):
		if(self.isReady()):
			return(self.readVoltage(),self.readCurrent(),self.readPower(),self.readRegPower())

	def close(self):
		self.ser.close()

		
if __name__ == "__main__":
	try:
		sensor = BTPOWER()
		print("Checking readiness")
		print(sensor.isReady())
		print("Reading voltage")
		voltage = sensor.readVoltage()
		print(type(voltage))
		print("Reading current")
		print(sensor.readCurrent())
		print("Reading power")
		print(sensor.readPower())
		print("reading registered power")
		print(sensor.readRegPower())
		print("reading all")
		print(sensor.readAll())
	finally:
		sensor.close()