PECMAC125A.py

#!/usr/bin/env python

# Distributed with a free-will license.
# Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
# PECMAC125A
# This code is designed to work with the PECMAC125A_DLCT03C20 I2C Mini Module available from ControlEverything.com.
# https://www.controleverything.com/content/Current?sku=PECMAC125A_DLCT03C20#tabs-0-product_tabset-2

import smbus
import time

# Get I2C bus
bus = smbus.SMBus(1)

# PECMAC125A address, 0x2A(42)
# Command for reading device identification data
# 0x6A(106), 0x02(2), 0x00(0),0x00(0), 0x00(0) 0x00(0), 0xFE(254)
# Header byte-2, command-2, byte 3, 4, 5 and 6 are reserved, checksum
command2 = [0x6A, 0x02, 0x00, 0x00, 0x00, 0x00, 0xFE]
bus.write_i2c_block_data(0x2A, 0x92, command2)

time.sleep(0.5)

# PECMAC125A address, 0x2A(42)
# Read data back from 0x55(85), 3 bytes
# Type of Sensor, Maximum Current, No. of Channels
data = bus.read_i2c_block_data(0x2A, 0x55, 3)

# Convert the data
typeOfSensor = data[0]
maxCurrent = data[1]
noOfChannel = data[2]

# Output data to screen
print("Type of Sensor : %d" %typeOfSensor)
print("Maximum Current : %d A" %maxCurrent)
print("No. of Channels : %d" %noOfChannel)

# PECMAC125A address, 0x2A(42)
# Command for reading current
# 0x6A(106), 0x01(1), 0x01(1),0x0C(12), 0x00(0), 0x00(0) 0x0A(10)
# Header byte-2, command-1, start channel-1, stop channel-12, byte 5 and 6 reserved, checksum
command1 = [0x6A, 0x01, 0x01, 0x0C, 0x00, 0x00, 0x0A]
bus.write_i2c_block_data(0x2A, 0x92, command1)

time.sleep(0.5)

# PECMAC125A address, 0x2A(42)
# Read data back from 0x55(85), No. of Channels * 3 bytes
# current MSB1, current MSB, current LSB
data1 = bus.read_i2c_block_data(0x2A, 0x55, noOfChannel*3+3)

# Convert the data
totalCurrent = 0
currents = []
print(data1)
for i in range(0, noOfChannel) :
	msb1 = data1[i * 3]
	msb = data1[1 + i * 3]
	lsb = data1[2 + i * 3]

	# Convert the data to ampere
	current = (msb1 * 65536 + msb * 256 + lsb) / 1000.0

	# Output data to screen
	print("Channel no : %d " %(i+1))
	print("  Current : %.2f A"%(current))
	print("  Usage   : %.2f kW"%(current*0.12))
	currents.append(current)
	totalCurrent += current

print("TOTAL")
print("  Current : %.2f A"%(totalCurrent))
print("  Usage   : %.2f kW"%(totalCurrent*0.120))

import time
datestamp = time.strftime("%Y-%m%b-%d-%a").lower()
logname = "usage/%s.log"%(datestamp)

f = open(logname, "a")
f.write("%d,%.4f,%.4f,%.4f\n"%
	(time.time(), totalCurrent,
	currents[0], currents[1]))
f.close()