diff --git a/.travis.yml b/.travis.yml
index e96947c..c8314d2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -35,7 +35,7 @@ matrix:
       script:
        - cppcheck --enable=all --inline-suppr --force --quiet --error-exitcode=1 Src/* Inc/* 
 
-    # Use pyflakes (or other tool) to check statically Python code
+    # Use pyflakes to check statically Python code
     - language: python
       dist: xenial
       sudo: true
diff --git a/README.md b/README.md
index 8dd9659..aac5971 100755
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ It is designed in a way that the device can work remotely, e.g. no connection vi
 
 Remarks:
 * Amplifier has three stages (first stage is transimpedance amplifier, not FET like most projects use). 
-* Amplifier has a separate power supply from 4x2V6 lithium batteries
+* Amplifier has a separate symmetric power supply from 2x2V6 lithium batteries
 
 
 ## Hardware
diff --git a/software/DataAcquisition/IonizationChamber.py b/software/DataAcquisition/IonizationChamber.py
index 191982c..eb0ca64 100644
--- a/software/DataAcquisition/IonizationChamber.py
+++ b/software/DataAcquisition/IonizationChamber.py
@@ -4,14 +4,15 @@ import mcp3425
 class IonizationChamber:
     def __init__(self, config):
         self.config = config
-        self.openSerialPort()
 
-    def openSerialPort(self):
+
+    def connect(self):
         self.serialPort = Serial(self.config.myDeviceId, baudrate = self.config.myBaudrate, timeout=None)
         self.serialPort.isOpen()
         self.serialPort.flushInput()
 
-    def acquireFromDevice(self):
+
+    def getMeasurement(self):
         dataIn = self.serialPort.read(5)
         (msb, lsb) = (dataIn[2], dataIn[3]) 
         deviceMeasurement = mcp3425.convert(msb, lsb, mcp3425.MCP3425_RESOLUTION.R14)
diff --git a/software/DataAcquisition/config.py b/software/DataAcquisition/config.py
index 8263eaf..4975ff9 100644
--- a/software/DataAcquisition/config.py
+++ b/software/DataAcquisition/config.py
@@ -1,3 +1,10 @@
+# ionization chamber
 myDeviceId = '/dev/ttyUSB0'
 myBaudrate = 9600 
 
+# dmm
+idDMM = "USB0::0x2A8D::0x1601::INSTR"
+testCommand = "READ?"
+
+
+useDMM = True
diff --git a/software/DataAcquisition/dmm.py b/software/DataAcquisition/dmm.py
index 0d69ea1..3fc6b14 100644
--- a/software/DataAcquisition/dmm.py
+++ b/software/DataAcquisition/dmm.py
@@ -1,30 +1,14 @@
-import datetime
-import csv
 import usbtmc
 
 class DMM:
-    def __init__(self, instrumentId):
-        self.device = usbtmc.Instrument(instrumentId)
-
-    def sendCmd(self, command):
-        return self.device.ask(command)
+    def __init__(self, config):
+        self.config = config
 
 
-if __name__ == "__main__":
-    testIterations = 50000
-    idDMM = "USB0::0x2A8D::0x1601::INSTR"
-    testCommand = "READ?"
-    plotYLabel = "voltage"
+    def connect(self):
+        self.device = usbtmc.Instrument(self.config.idDMM)
 
-    dmm = DMM(idDMM)
 
-    with open('SampleOutputFile.csv', mode='w') as sampleOutputFile:
-        sampleOutputFileWriter = csv.writer(sampleOutputFile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
-        sampleOutputFileWriter.writerow(["Timestamp", "Measurement"])
+    def getMeasurement(self):
+         return self.device.ask(self.config.testCommand)
 
-        while(True):
-            sampleData = float(dmm.sendCmd(testCommand))
-            now = datetime.datetime.now()
-
-            sampleOutputFileWriter.writerow([now, sampleData])
-            sampleOutputFile.flush()
\ No newline at end of file
diff --git a/software/DataAcquisition/drawDiagramSingle.R b/software/DataAcquisition/drawDiagramSingle.R
index 863bb4d..7895bc9 100644
--- a/software/DataAcquisition/drawDiagramSingle.R
+++ b/software/DataAcquisition/drawDiagramSingle.R
@@ -8,9 +8,8 @@ Sys.setenv(LANG = "en")
 drawDiagramSingle <- function(samples) {
 
     # date column should be type of date, not string, so parse it
-    png(filename = paste0("results-", format(Sys.time(), "%d_%b_%Y_%H_%M"), ".png"), width = 800, height = 900, bg = "white")
-
-    # create graphs
+    png(filename = paste0("results-", format(Sys.time(), "%d_%b_%Y_%H_%M"), ".png"), 
+        width = 800, height = 900, bg = "white")
 
     samples$Time = as.POSIXct(samples$Time, format="%Y-%m-%d %H:%M:%S.%OS")
 
@@ -21,8 +20,7 @@ drawDiagramSingle <- function(samples) {
                     grid = TRUE, 
                     col.line = "black",
                     ylab = "counts per minute",
-            ylim=c(min(samples$Counter), max(samples$Counter)),
-
+                    ylim=c(min(samples$Counter), max(samples$Counter)),
                     xlim=c(min(samples$Time), max(samples$Time)),
                     main = "Change over time")
 
diff --git a/software/DataAcquisition/main.R b/software/DataAcquisition/main.R
index a1cebbf..38675ca 100644
--- a/software/DataAcquisition/main.R
+++ b/software/DataAcquisition/main.R
@@ -9,3 +9,7 @@ samples <- read.delim(inputFileName, , sep=",")
 
 drawDiagramSingle(samples)
 
+# TODO move to a separate module
+library(Hmisc)
+rcorr(samples$Counter,samples$DMM, type="pearson")
+
diff --git a/software/DataAcquisition/main.py b/software/DataAcquisition/main.py
index f8e656a..1057f38 100644
--- a/software/DataAcquisition/main.py
+++ b/software/DataAcquisition/main.py
@@ -1,38 +1,72 @@
 import datetime
 
 from IonizationChamber import IonizationChamber 
+from dmm import DMM
 import config
 
 class IonizationChamberStateMachine:
     def __init__(self, config):
         self.config = config
-        self.chamber = IonizationChamber(config)
+        self.deviceMeasurement = 0.0
+        self.dmmMeasurement = 0.0
+        
         self.nextState = self.initIonizationChamber
 
+
     def tick(self):
         self.nextState()
 
+
     def initIonizationChamber(self):
-        self.chamber.openSerialPort()
+        self.chamber = IonizationChamber(config)
+        self.chamber.connect()
+        
+        if config.useDMM:
+            self.nextState = self.initDMM
+        else:
+            self.nextState = self.initOutputFile
+
+
+    def initDMM(self):
+        self.dmm = DMM(config)
+        self.dmm.connect()
+        
         self.nextState = self.initOutputFile
 
+
     def initOutputFile(self):
         self.logFile = open('data.csv', 'w')
-        self.logFile.write("Time,Counter\n")
+        self.logFile.write("Time,Counter,DMM\n")
+        
         self.nextState = self.getMeasurementFromIonizationChamber
 
+
     def getMeasurementFromIonizationChamber(self):
-        self.deviceMeasurement = self.chamber.acquireFromDevice()
+        self.deviceMeasurement = self.chamber.getMeasurement()
+        
+        if config.useDMM:
+            self.nextState = self.getMeasurementFromDMM
+        else:
+            self.nextState = self.saveMeasurement
+
+
+    def getMeasurementFromDMM(self):
+        self.dmmMeasurement = self.dmm.getMeasurement()
+        
         self.nextState = self.saveMeasurement
 
+
     def saveMeasurement(self):
         now = datetime.datetime.now()
-        self.logFile.write("{0},{1}\n".format(now, self.deviceMeasurement))
+        self.logFile.write("{0},{1},{2}\n".format(now, self.deviceMeasurement, self.dmmMeasurement))
         self.logFile.flush()
+        
         self.nextState = self.showMeasurementToUser
 
+
     def showMeasurementToUser(self):
-        print(self.deviceMeasurement)
+        print("{0}, {1}".format(self.deviceMeasurement, self.dmmMeasurement))
+        
         self.nextState = self.getMeasurementFromIonizationChamber