PowerVoltageGraph.py

# PowerVoltageGraph  
# filename: VoltageGraph.py
# Version 1.3 09/12/13
# Version 1.4 03/30/15
#
# contains event routines for data collection
#
#

import sys
import time
import RPi.GPIO as GPIO

import gc
import datetime

import matplotlib
# Force matplotlib to not use any Xwindows backend.
matplotlib.use('Agg')

from matplotlib import pyplot
from matplotlib import dates

import pylab

import MySQLdb as mdb

# Check for user imports
try:
        import conflocal as config
except ImportError:
        import config

def  PowerVoltageGraph(source,days,delay):


    
    print("PowerVoltageGraph source:%s days:%s delay:%i" % (source,days,delay))
    print("sleeping :",delay)
    time.sleep(delay)
    print("PowerVoltageGraph running now")
    
    # now we have get the data, stuff it in the graph 

    try:
        print("trying database")
        db = mdb.connect(config.MySQL_Address, config.MySQL_User, config.MySQL_Password, config.MySQL_Database);
        cursor = db.cursor()
        query = "SELECT TimeStamp, solarVoltage, batteryVoltage, loadVoltage FROM PowerSystem where  now() - interval %i hour < TimeStamp" % (days*24)
        cursor.execute(query)
        result = cursor.fetchall()

        t = []
        s = []
        u = []
        v = []
        #x = []
        
        for record in result:
            t.append(record[0])
            s.append(record[1])
            u.append(record[2])
            v.append(record[3])
            #x.append(record[4])
        fig = pyplot.figure()

        print ("count of t=",len(t))
        #print (t)
        if (len(t) == 0):
            return
        #dts = map(datetime.datetime.fromtimestamp, t)
        #print dts
        #fds = dates.date2num(t) # converted
        # matplotlib date format object
        hfmt = dates.DateFormatter('%m/%d-%H')

        fig = pyplot.figure()
        fig.set_facecolor('white')
        ax = fig.add_subplot(111,facecolor = 'white')
        #ax.vlines(fds, -200.0, 1000.0,colors='w')

        ax.xaxis.set_major_locator(dates.HourLocator(interval=6))
        ax.xaxis.set_major_formatter(hfmt)
        ax.set_ylim(bottom = -200.0)
        pyplot.xticks(rotation='vertical')
        pyplot.subplots_adjust(bottom=.3)
        pylab.plot(t, s, color='b',label="Solar",linestyle="-",marker=".")
        pylab.plot(t, u, color='r',label="Battery",linestyle="-",marker=".")
        pylab.plot(t, v, color='g',label="Load",linestyle="-",marker=".")
        #pylab.plot(t, x, color='m',label="Power Eff",linestyle="-",marker=".")
        pylab.xlabel("Hours")
        pylab.ylabel("Voltage V")
        pylab.legend(loc='upper left')

        if (max(u) > max(s)):
            myMax = max(u)+ 100.0
        else:
            myMax = max(s)
        pylab.axis([min(t), max(t), min(u), myMax])
        pylab.figtext(.5, .05, ("SkyWeather Power Voltage Last %i Days" % days),fontsize=18,ha='center')
        pyplot.setp( ax.xaxis.get_majorticklabels(), rotation=70)

        pylab.grid(True)

        pyplot.show()
        pyplot.savefig("./static/PowerVoltageGraph.png",facecolor=fig.get_facecolor())    


    except mdb.Error as e:
            print ("Error %d: %s" % (e.args[0],e.args[1]))
    finally:    

        cursor.close()            
        db.close()

        del cursor
        del db

        fig.clf()
        pyplot.close()
        pylab.close()
        del t, s, u, v
        gc.collect()
        print("PowerVoltageGraph finished now")