diff -u -r1.2 -r1.3
--- HpsSiSensor.java	10 Oct 2013 01:46:54 -0000	1.2
+++ HpsSiSensor.java	11 Oct 2013 00:56:07 -0000	1.3
@@ -11,33 +11,30 @@

 import org.lcsim.detector.identifier.IIdentifierHelper;
 
 /**

- * This class extends {@link SiSensor} with HPS-specific functionality.  Since there are 
- * a large number of extra parameters that would need to be included in a fully
- * qualified class constructor, public setters are used instead.

+ * This class extends {@link SiSensor} with information specific to HPS SVT sensors,
+ * including FPGA and hybrid numbers, as well as time variant conditions data per channel
+ * such as gain, noise, etc.  

  * @author Jeremy McCormick <[log in to unmask]>
  */
 public class HpsSiSensor extends SiSensor {
 

-	// Sensor setup information.
-	int fpga;
-	int hybrid;
-	int layer;
-	int nchannels;
-	boolean top;
-	boolean axial;

+	/** Hardware setup information. */
+	protected int fpga;
+	protected int hybrid;
+	private final static int DEFAULT_CHANNELS = 640;
+	protected int nchannels = DEFAULT_CHANNELS;

-	// Time variable conditions data.

+	/** Time variant conditions data. */

 	Map<Integer,Double> pedestalMap = new HashMap<Integer,Double>();	
 	Map<Integer,Double> noiseMap = new HashMap<Integer,Double>();
 	Map<Integer,Double> offsetMap = new HashMap<Integer,Double>();

+	Map<Integer,Double> gainMap = new HashMap<Integer,Double>();

 	Map<Integer,Double> t0Map = new HashMap<Integer,Double>();
 	Map<Integer,double[]> pulseParameterMap = new HashMap<Integer,double[]>();
 	Set<Integer> badChannels = new HashSet<Integer>();

-	
-	private static final boolean debug = true;
-	

+		

 	/**

-	 * This class constructor matches that of <code>SiSensor</code>.

+	 * This class constructor matches the signature of <code>SiSensor</code>.

 	 * @param sensorid The sensor ID.
 	 * @param name The name of the sensor.
 	 * @param parent The parent DetectorElement.

@@ -52,24 +49,40 @@

             IIdentifier id)
     {
 		super(sensorid, name, parent, support, id);

-		if (debug)
-			System.out.println("created HpsSiSensor: " + name);

     }
 	
 	/**

-	 * Get whether this sensor is in a top layer.

+	 * Get whether this sensor is in the top half of the detector.
+	 * Modules in the top half have module numbers of 0 or 2.

 	 * @return True if sensor is in top layer; false if not.
 	 */
 	public boolean isTopLayer() {

-		return top;

+		return getModuleNumber() % 2 == 0;

 	}
 	
 	/**

-	 * Get whether this sensor is in a bottom layer.

+	 * Get whether this sensor is in the bottom half of the detector.
+	 * Modules in the bottom half have module numbers of 1 or 3.

 	 * @return True if sensor is in bottom layer; false if not.
 	 */
 	public boolean isBottomLayer() {

-		return top == false;

+		return getModuleNumber() % 2 != 0;
+	}
+	
+	/**
+	 * Get the module number of the sensor.
+	 * @return The module number of the sensor.
+	 */
+	public int getModuleNumber() {
+		return getTrackerIdHelper().getModuleValue(getIdentifier());
+	}
+	
+	/**
+	 * Get the specific type of identifier helper for this component.
+	 * @return The identifier helper.
+	 */
+	public SiTrackerIdentifierHelper getTrackerIdHelper() {
+		return (SiTrackerIdentifierHelper)getIdentifierHelper();

 	}
 
 	/**

@@ -77,9 +90,14 @@

 	 * @return True if sensor is axial; false if not.
 	 */
 	public boolean isAxial() {

-		return axial;

+        if (this.isTopLayer() && getLayerNumber() % 2 == 1) {
+            return true;
+        } else if (!isTopLayer() && getLayerNumber() % 2 == 0) {
+            return true;
+        }
+        return false;

 	}

-

+		

 	/**
 	 * Get the pedestal for the given channel.
 	 * @param channel The channel number.

@@ -97,6 +115,16 @@

 	public Double getNoise(int channel) {
 		return noiseMap.get(channel);
 	}

+	
+	/**
+	 * Get the gain for the given channel.
+	 * @param channel The channel number.
+	 * @return The gain value for the channel or null if not set.
+	 * 
+	 */
+	public Double getGain(int channel) {
+		return gainMap.get(channel);
+	}	

 
 	/**
 	 * Get the time offset for the given channel.

@@ -172,7 +200,7 @@

 	 * @return The layer number of the sensor.
 	 */
 	public int getLayerNumber() {

-		return layer;

+		return getIdentifierHelper().getValue(getIdentifier(), "layer");

 	}
 
 	/**

@@ -188,24 +216,7 @@

 		expId.setValue(idx, channel);
 		return helper.pack(expId).getValue();
 	}

-	
-	/**
-	 * Set this sensor as being in the top layer or not.
-	 * If this is set to false, then it is assumed to be in the bottom layer.
-	 * @param top The top layer setting.
-	 */
-	public void setTopLayer(boolean top) {
-		this.top = top;
-	}
-	
-	/**
-	 * Set whether or not this sensor is axial.
-	 * @param axial The axial setting.
-	 */
-	public void setAxial(boolean axial) {
-		this.axial = axial;
-	}
-	

+		

 	/**
 	 * Set the pedestal value for the given channel.
 	 * @param channel The channel number.

@@ -223,6 +234,15 @@

 	public void setNoise(int channel, double noise) {
 		noiseMap.put(channel, noise);
 	}

+	
+	/**
+	 * Set the gain value for the given channel.
+	 * @param channel The channel number.
+	 * @param gain The gain value.
+	 */
+	public void setGain(int channel, double gain) {
+		gainMap.put(channel, gain);
+	}

 
 	/**
 	 * Set the time offset for the given channel.

@@ -262,7 +282,7 @@

 	}
 	
 	/**

-	 * Set the number of channels in this sensor.

+	 * Set the number of channels in this sensor.	

 	 * @param nchannels The number of channels in the sensor.
 	 */
 	public void setNumberOfChannels(int nchannels) {

@@ -284,19 +304,11 @@

 	public void setHybridNumber(int hybrid) {
 		this.hybrid = hybrid;
 	}

-
-	/**
-	 * Set the layer number of the sensor.
-	 * @param layer The layer number.
-	 */
-	public void setLayerNumber(int layer) {
-		this.layer = layer;
-	}

 	
 	/**

-	 * Reset the time dependent conditions of this sensor.

+	 * Reset the time dependent conditions data of this sensor.

 	 * This does NOT reset the sensor setup information, which is

-	 * assumed to be fixed once set.

+	 * assumed to be fixed once it is setup for a given session.

 	 */
 	public void reset() {
 		pedestalMap.clear();	

@@ -305,5 +317,6 @@

 		t0Map.clear();
 		pulseParameterMap.clear();
 		badChannels.clear();

+		gainMap.clear();

 	}
 }

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