Changed the WaveGen to save the current analog output values

at the beginning of the scan, and to restore them at the end.
This prevents the issue of the ao record values not matching
the actual output voltage at the end of the scan.

measCompApp/src/drvMultiFunction.cpp

@@ -774,6 +774,7 @@ class MultiFunction : public asynPortDriver {
   int numWaveGenChans_;
   int numWaveDigChans_;
   int pulseGenRunning_[MAX_PULSE_GEN];
+  int waveGenSavedOutput[MAX_ANALOG_OUT];
   int waveGenRunning_;
   int waveDigRunning_;
   int startPulseGenerator(int timerNum);
@@ -1585,6 +1586,8 @@ int MultiFunction::startWaveGen()
       firstChan = i;
       firstType = waveType;
     }
+    // Save the current value of the analog output so it can be restored at the end of the scan
+    getIntegerParam(i, analogOutValue_, &waveGenSavedOutput[i]);
     // Cannot mix user-defined and internal waveform types, because internal modifies dwell time
     // based on frequency
     if (((firstType == waveTypeUser) && (waveType != waveTypeUser)) ||
@@ -1674,14 +1677,34 @@ int MultiFunction::startWaveGen()
 int MultiFunction::stopWaveGen()
 {
   int err;
+  int range;
+  int enable;
+  int status=0;
   waveGenRunning_ = 0;
+  static const char *functionName = "stopWaveGen";
+
   setIntegerParam(waveGenRun_, 0);
   ULMutex.lock();
   #ifdef _WIN32
     err = cbStopBackground(boardNum_, AOFUNCTION);
   #else
     err = ulAOutScanStop(daqDeviceHandle_);
   #endif
+
+  // Set the analog outputs back to their value before the scan
+  for (int i=0; i<numAnalogOut_; i++) {
+    getIntegerParam(i, waveGenEnable_, &enable);
+    if (!enable) continue;
+    getIntegerParam(i, analogOutRange_, &range);
+    #ifdef _WIN32
+      status = cbAOut(boardNum_, i, range, waveGenSavedOutput[i]);
+    #else
+      Range ulRange;
+      mapRange(range, &ulRange);
+      status = ulAOut(daqDeviceHandle_, i, ulRange, AOUT_FF_NOSCALEDATA, (double) waveGenSavedOutput[i]);
+    #endif
+    reportError(status, functionName, "calling AOut");
+  }
   ULMutex.unlock();
   return err;
 }