Minimum step time (default=42ms)

src/main/java/Scienta.java

@@ -28,6 +28,7 @@ public class Scienta extends AreaDetector {
     final Stats[] stats;
     final String channelCtrl;
     int frameTime = 14;
+    int minStepTime = 42;
 
     public Scienta(final String name, final String channelPrefix) {
         this(name, channelPrefix + ":cam1", channelPrefix + ":image1");
@@ -130,7 +131,8 @@ public class Scienta extends AreaDetector {
             public void onValueChanged(Device device, Object value, Object former) {
                 int time_ms = (int) (((Double) value) * 1000);
                 int num_frames = time_ms / getFrameTimeMs();
-                if (num_frames != frames.take()){
+                Integer cur  = frames.take();
+                if ((cur==null) || (num_frames != cur)){
                     frames.writeAsync(num_frames);
                 }
             }
@@ -139,9 +141,7 @@ public class Scienta extends AreaDetector {
             public void onValueChanging(Device device, Object value, Object former) throws Exception {
                 //Value must be multiple of getFrameTimeMs()
                 int val_ms = (int) (((Double) value) * 1000);
-                if ((val_ms % getFrameTimeMs()) != 0){
-                    throw new IOException("Value must be multiple of " + getFrameTimeMs() + "ms");
-                }                                
+                checkTimeValue(val_ms);
             }
         });
         
@@ -161,12 +161,30 @@ public class Scienta extends AreaDetector {
     
     public int getFrameTimeMs() {
         return frameTime;
-    }
+    }        
 
     public void setFrameTimeMs(int value) {
         frameTime = value;
     }    
 
+    public int getMinStepTimeMs() {
+        return minStepTime;
+    }        
+
+    public void setMinStepTimeMs(int value) {
+        minStepTime = value;
+    }    
+    
+    public void checkTimeValue(int val_ms) throws IOException{
+        if ((val_ms % getFrameTimeMs()) != 0){
+            throw new IOException("Value must be multiple of " + getFrameTimeMs() + "ms");
+        }                                
+        if (val_ms < getMinStepTimeMs()){
+            throw new IOException("Value must be equal or greater than " + getMinStepTimeMs() + "ms");
+        }                                
+        
+    }
+
     public class ScientaSpectrum extends ChannelDoubleArray implements ReadableCalibratedArray<double[]> {
 
         ScientaSpectrum() {