diff --git a/include/Keithley_6485.h b/include/Keithley_6485.h
index a8c9de0651e2263f446edfa100a9eb0607150654..a02dfeb99abb1cc87355099906729515b91014c2 100644
--- a/include/Keithley_6485.h
+++ b/include/Keithley_6485.h
@@ -63,7 +63,7 @@ public:
 	/**
 	*  \brief Methods to configure the integration mode.
 	*/
-  void set_knplc        (float);
+  void set_knplc        (double);
   void set_triggercount (short);
   void set_buffer_size  (short);
 	void init_keithley		(void); 
diff --git a/include/Keithley_6487.h b/include/Keithley_6487.h
index 67cf108ef91f394861ac1946859363dd0562316a..255aa4926bfbe73868a95d960cb709c737a24f3e 100644
--- a/include/Keithley_6487.h
+++ b/include/Keithley_6487.h
@@ -68,7 +68,7 @@ public:
 	/**
 	*  \brief Methods to configure the integration mode.
 	*/
-  void set_knplc        (float);
+  void set_knplc        (double);
   void set_triggercount (short);
   void set_buffer_size  (short);
 	void init_keithley		(void); 
diff --git a/include/Keithley_6514.h b/include/Keithley_6514.h
index f2346401360bbbad841304a2738484ad6c1729d1..621116506af2dd18f3a98da41de92dd6a3cdc911 100644
--- a/include/Keithley_6514.h
+++ b/include/Keithley_6514.h
@@ -71,7 +71,7 @@ public:
 	/**
 	*  \brief Methods to configure the integration mode.
 	*/
-  void set_knplc        (float);
+  void set_knplc        (double);
   void set_triggercount (short);
   void set_buffer_size  (short);
 	void init_keithley		(void); 
diff --git a/include/Keithley_6517.h b/include/Keithley_6517.h
index cffe442262f08341aee694033e70c6ceb5fd4c39..05f331256077aba32eda086c1a118397591d64f7 100644
--- a/include/Keithley_6517.h
+++ b/include/Keithley_6517.h
@@ -75,7 +75,7 @@ public:
 	/**
 	*  \brief Methods to configure the integration mode.
 	*/
-  void set_knplc        (float);
+  void set_knplc        (double);
   void set_triggercount (short);
   void set_buffer_size  (short);
 	void init_keithley		(void); 
diff --git a/src/Keithley_6485.cpp b/src/Keithley_6485.cpp
index 9174d00ec6a7fb8788de869f4b3ce57a63d3c9a8..e3b83cda4517071418a1b05849f5f0832912ea47 100644
--- a/src/Keithley_6485.cpp
+++ b/src/Keithley_6485.cpp
@@ -222,7 +222,7 @@ std::vector<double> Keithley_6485::get_fetchValue (void)
 // ============================================================================
 // Keithley_6485::set_knplc
 // ============================================================================
-void Keithley_6485::set_knplc (float numPLC) 
+void Keithley_6485::set_knplc (double numPLC) 
 {
 std::stringstream cmd_to_send;
 
diff --git a/src/Keithley_6487.cpp b/src/Keithley_6487.cpp
index 9c5998fd07fcd640ae4f14bf6e0866ff7cd363eb..357907222396191196d33aece4d5c3ee18350c15 100644
--- a/src/Keithley_6487.cpp
+++ b/src/Keithley_6487.cpp
@@ -228,7 +228,7 @@ double delta = 0;
 // ============================================================================
 // Keithley_6487::set_knplc
 // ============================================================================
-void Keithley_6487::set_knplc (float numPLC) 
+void Keithley_6487::set_knplc (double numPLC) 
 {
 std::stringstream cmd_to_send;
 
diff --git a/src/Keithley_6514.cpp b/src/Keithley_6514.cpp
index b8dae17a5771f3e3583e1626dbd2ab42452520c2..914588a7184559dc551c7daca0e7f3d130925746 100644
--- a/src/Keithley_6514.cpp
+++ b/src/Keithley_6514.cpp
@@ -366,7 +366,7 @@ double delta = 0;
 // ============================================================================
 // Keithley_6514::set_knplc
 // ============================================================================
-void Keithley_6514::set_knplc (float numPLC) 
+void Keithley_6514::set_knplc (double numPLC) 
 {
 std::stringstream cmd_to_send;
 
diff --git a/src/Keithley_6517.cpp b/src/Keithley_6517.cpp
index 16ce41f5bdd44ab21ba01739c01f35d286686fe2..0da00d057130da44c8a44902c5ddf2705d81e5bc 100644
--- a/src/Keithley_6517.cpp
+++ b/src/Keithley_6517.cpp
@@ -432,7 +432,7 @@ void Keithley_6517::averageStateOFF (void)
 // ============================================================================
 // Keithley_6517::set_knplc
 // ============================================================================
-void Keithley_6517::set_knplc (float numPLC) 
+void Keithley_6517::set_knplc (double numPLC) 
 {
 std::stringstream cmd_to_send;