diff --git a/simuLines.py b/simuLines.py
index c7cb44b..6925cb5 100755
--- a/simuLines.py
+++ b/simuLines.py
@@ -11,7 +11,7 @@ from gwpy.time import tconvert
 import datetime
 import configparser
 import numpy as np
-from multiprocessing import Process, Queue, Manager
+from multiprocessing import Process, Queue, Manager, Lock
 import cdsutils
 import h5py
 import logging
@@ -42,6 +42,9 @@ logger.addHandler(file_handler)
 logger.addHandler(stdout_handler)
 ###/Python Logger boiler plate
 
+# lock used to block processes from sending at the same time
+awg_lock = Lock()
+
 class ResultsObject():
     '''
     This object defines how data is collected within each swept sine measurement.
@@ -481,19 +484,68 @@ def SignalInjection(resultobj, freqAmp):
     
     #Driving the excitations with ramp up, settle time and ramp down.
     logger.info('Drive, on ' + resultobj.scanName + ', at frequency: ' + str(freqAmp[0])+ ', is now running for '+str(fullDuration + rampUp + rampDown + settleTime + 1) + ' seconds.')
-    drive.start(ramptime=rampUp) #this is blocking, and starts on a GPS second.
+
+    start_drive(drive, rampUp) #this is blocking, and starts on a GPS second.
+
     time.sleep(np.ceil(settleTime)) #this will soak at least half of that +1 second buffer. Having at least that one second assures that the time windows are actually after sette time.
     #start of real data acquisition should also be exactly a GPS second
     #tconvert('now') gives the floor of the current GPS second.
     timeWindowStart = int(tconvert('now'))
     time.sleep(fullDuration)
     timeWindowEnd = int(tconvert('now'))
-    drive.stop(ramptime=rampDown)# you'd think 'wait = false' skips the sleep and saves time? No, it just fails to ramp down when a new start is called, since commands sent to a channel override previous commands. :( No beuno.
+
+    stop_drive(drive,rampDown)
+
     #write the start and stop times to the results object for later processing.
     logger.info('Drive, on ' + resultobj.scanName + ', at frequency: ' + str(freqAmp[0])+ ', is finished. GPS start and end time stamps: '+str(timeWindowStart)+', '+str(timeWindowEnd))
     for iteration in range(len(resultobj.channelB)): #One TF is defined by each A and B pair.
         resultobj.saveTimeFlags(str(freqAmp[0]), timeWindowStart, timeWindowEnd, singleDuration, iteration)
 
+
+def start_drive(drive, rampUp):
+    """Safely start a drive, but without blocking
+    other commands from other processes for long."""
+
+    # set the gain to 0 before starting excitation, because
+    # we need to use the gain later to ramp up the excitatioin
+    awg_lock.acquire()
+    drive.set_gain(0.0, wait=False)
+    awg_lock.release()
+
+    # sleep two epochs (1/8 sec) to make sure gain is set
+    time.sleep(1 / 8.0);
+
+    awg_lock.acquire()
+    drive.start(ramptime=0, wait=False)
+    awg_lock.release()
+
+    # sleep two epochs (1/8 sec)to make sure sine wave is started
+    time.sleep(1 / 8.0);
+
+    # ramp up the drive using the gain
+    awg_lock.acquire()
+    drive.set_gain(1.0, ramptime=rampUp, wait=False)
+    awg_lock.release()
+
+    # wait for the ramp up to finish
+    time.sleep(rampUp + 1 / 8.0)
+
+
+def stop_drive(drive, rampDown):
+
+    # start thre ramp down
+    awg_lock.acquire()
+    drive.set_gain(0, ramptime=rampDown, wait=False)
+    awg_lock.release()
+
+    # wait for the ramp down to finish
+    time.sleep(rampDown + 1 / 8.0)
+
+    awg_lock.acquire()
+    drive.stop()
+    awg_lock.release()
+
+
 def scanToFilenameMap(scan):
     if scan == 'DARM_OLGTF':
         return 'DARMOLG_SS'