diff --git a/Makefile b/Makefile
index 12c7651..ed8e06b 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 
 UNAME := $(shell uname)
 
-OBJS = cmd.o command.o pixel_dtb.o protocol.o psi46test.o rpc.o rpc_calls.o settings.o usb.o plot.o datastream.o analyzer.o chipdatabase.o defectlist.o pixelmap.o prober.o ps.o linux/rs232.o color.o error.o histo.o profiler.o scanner.o test_dig.o
+OBJS = cmd.o command.o pixel_dtb.o protocol.o psi46test.o rpc.o rpc_calls.o settings.o usb.o plot.o datastream.o analyzer.o chipdatabase.o defectlist.o pixelmap.o prober.o ps.o linux/rs232.o color.o error.o histo.o profiler.o scanner.o test_dig.o rpc_error.o
 
 ifeq ($(UNAME), Darwin)
 CXXFLAGS = -g -Os -Wall -I/usr/local/include -Wno-logical-op-parentheses -I/usr/X11/include
diff --git a/psi46test.cpp b/psi46test.cpp
index 5780043..fbbf54d 100644
--- a/psi46test.cpp
+++ b/psi46test.cpp
@@ -89,7 +89,7 @@ int main(int argc, char* argv[])
 				tb.Welcome();
 				tb.Flush();
 			}
-			catch(CRpcError e)
+			catch(CRpcError &e)
 			{
 				e.What();
 				printf("ERROR: DTB software version could not be identified, please update it!\n");
@@ -122,7 +122,7 @@ int main(int argc, char* argv[])
 
 		cmd();
 	}
-	catch (CRpcError e)
+	catch (CRpcError &e)
 	{
 		e.What();
 	}
diff --git a/psi46test.sln b/psi46test.sln
index a7dd232..feb81da 100644
--- a/psi46test.sln
+++ b/psi46test.sln
@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 11.00
 # Visual Studio 2010
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "psi46test", "psi46test.vcxproj", "{C111528D-1041-29DE-0E8F-449670F1297A}"
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "psi46test", "psi46test.vcxproj", "{6F2009B6-583C-0C19-B3FF-CCB495403FBA}"
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "rpcgen", "rpcgen\rpcgen.vcxproj", "{0E9701FB-B917-4198-86ED-7E29D670A201}"
 EndProject
@@ -11,10 +11,10 @@ Global
 		Release|Win32 = Release|Win32
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{C111528D-1041-29DE-0E8F-449670F1297A}.Debug|Win32.ActiveCfg = Debug|Win32
-		{C111528D-1041-29DE-0E8F-449670F1297A}.Debug|Win32.Build.0 = Debug|Win32
-		{C111528D-1041-29DE-0E8F-449670F1297A}.Release|Win32.ActiveCfg = Release|Win32
-		{C111528D-1041-29DE-0E8F-449670F1297A}.Release|Win32.Build.0 = Release|Win32
+		{6F2009B6-583C-0C19-B3FF-CCB495403FBA}.Debug|Win32.ActiveCfg = Debug|Win32
+		{6F2009B6-583C-0C19-B3FF-CCB495403FBA}.Debug|Win32.Build.0 = Debug|Win32
+		{6F2009B6-583C-0C19-B3FF-CCB495403FBA}.Release|Win32.ActiveCfg = Release|Win32
+		{6F2009B6-583C-0C19-B3FF-CCB495403FBA}.Release|Win32.Build.0 = Release|Win32
 		{0E9701FB-B917-4198-86ED-7E29D670A201}.Debug|Win32.ActiveCfg = Debug|Win32
 		{0E9701FB-B917-4198-86ED-7E29D670A201}.Debug|Win32.Build.0 = Debug|Win32
 		{0E9701FB-B917-4198-86ED-7E29D670A201}.Release|Win32.ActiveCfg = Release|Win32
diff --git a/psi46test.vcxproj b/psi46test.vcxproj
index c06214b..5604d26 100644
--- a/psi46test.vcxproj
+++ b/psi46test.vcxproj
@@ -161,6 +161,7 @@
     <ClCompile Include="psi46test.cpp" />
     <ClCompile Include="rpc.cpp" />
     <ClCompile Include="rpc_calls.cpp" />
+    <ClCompile Include="rpc_error.cpp" />
     <ClCompile Include="test_dig.cpp" />
     <ClCompile Include="usb.cpp">
       <AssemblerOutput Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">All</AssemblerOutput>
diff --git a/psi46test.vcxproj.filters b/psi46test.vcxproj.filters
index ed26b8a..0b582b8 100644
--- a/psi46test.vcxproj.filters
+++ b/psi46test.vcxproj.filters
@@ -90,6 +90,9 @@
     <ClCompile Include="win32\rs232.cpp">
       <Filter>Quellcodedateien</Filter>
     </ClCompile>
+    <ClCompile Include="rpc_error.cpp">
+      <Filter>Quellcodedateien</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="command.h">
diff --git a/rpc.h b/rpc.h
index 6e53252..1ad5906 100644
--- a/rpc.h
+++ b/rpc.h
@@ -48,7 +48,8 @@ extern const char rpc_timestamp[];
 		rpc_cmdId[x] = id = GetRpcCallId(name); \
 		if (id >= 0) return id; \
 		throw CRpcError(CRpcError::UNKNOWN_CMD); \
-	}
+	} \
+	friend class CRpcError;
 
 #define RPC_INIT rpc_io = &RpcIoNull; rpc_cmdId = new int[rpc_cmdListSize]; rpc_Clear();
 
diff --git a/rpc_error.cpp b/rpc_error.cpp
new file mode 100644
index 0000000..f25cb87
--- /dev/null
+++ b/rpc_error.cpp
@@ -0,0 +1,43 @@
+// rpc_error.cpp
+
+#include "rpc_error.h"
+#include "pixel_dtb.h"
+
+
+const char *CRpcError::GetMsg()
+{
+	switch (error)
+	{
+		case OK:              return "OK";
+		case TIMEOUT:         return "TIMEOUT";
+		case WRITE_ERROR:     return "WRITE_ERROR";
+		case READ_ERROR:      return "READ_ERROR";
+		case READ_TIMEOUT:    return "READ_TIMEOUT";
+		case MSG_UNKNOWN:     return "MSG_UNKNOWN";
+		case WRONG_MSG_TYPE:  return "WRONG_MSG_TYPE";
+		case WRONG_DATA_SIZE: return "WRONG_DATA_SIZE";
+		case ATB_MSG:         return "ATB_MSG";
+		case WRONG_CGRP:      return "WRONG_CGRP";
+		case WRONG_CMD:       return "WRONG_CMD";
+		case CMD_PAR_SIZE:    return "CMD_PAR_SIZE";
+		case NO_DATA_MSG:     return "NO_DATA_MSG";
+		case NO_CMD_MSG:      return "NO_CMD_MSG";
+		case UNKNOWN_CMD:     return "UNKNOWN_CMD";
+		case UNDEF:           return "UNDEF";
+	}
+	return "?";
+}
+
+
+void CRpcError::What()
+{
+	if (functionId >= 0)
+	{
+		std::string fname(CTestboard::rpc_cmdName[functionId]);
+		std::string fname_pretty;
+		rpc_TranslateCallName(fname, fname_pretty);
+		printf("\n%s\nERROR: %s\n", fname_pretty.c_str(), GetMsg());
+	}
+	else
+		printf("ERROR: %s\n", GetMsg());
+}
diff --git a/rpc_error.h b/rpc_error.h
index 7f3ed71..42b0a67 100644
--- a/rpc_error.h
+++ b/rpc_error.h
@@ -3,6 +3,8 @@
 #pragma once
 
 #include <stdio.h>
+#include <string>
+
 
 class CRpcError
 {
@@ -26,33 +28,10 @@ class CRpcError
 		UNKNOWN_CMD,
 		UNDEF
 	} error;
-	CRpcError() : error(CRpcError::OK) {}
+	int functionId;
+	CRpcError() : error(CRpcError::OK), functionId(-1) {}
 	CRpcError(errorId e) : error(e) {}
-	const char *GetMsg()
-	{
-		switch (error)
-		{
-			case OK:              return "OK";
-			case TIMEOUT:         return "TIMEOUT";
-			case WRITE_ERROR:     return "WRITE_ERROR";
-			case READ_ERROR:      return "READ_ERROR";
-			case READ_TIMEOUT:    return "READ_TIMEOUT";
-			case MSG_UNKNOWN:     return "MSG_UNKNOWN";
-			case WRONG_MSG_TYPE:  return "WRONG_MSG_TYPE";
-			case WRONG_DATA_SIZE: return "WRONG_DATA_SIZE";
-			case ATB_MSG:         return "ATB_MSG";
-			case WRONG_CGRP:      return "WRONG_CGRP";
-			case WRONG_CMD:       return "WRONG_CMD";
-			case CMD_PAR_SIZE:    return "CMD_PAR_SIZE";
-			case NO_DATA_MSG:     return "NO_DATA_MSG";
-			case NO_CMD_MSG:      return "NO_CMD_MSG";
-			case UNKNOWN_CMD:     return "UNKNOWN_CMD";
-			case UNDEF:           return "UNDEF";
-		}
-		return "?";
-	}
-	void What()
-	{
-		printf("ERROR: %s\n", GetMsg());
-	}
+	void SetFunction(unsigned int cmdId) { functionId = cmdId; }
+	const char *GetMsg();
+	void What();
 };
diff --git a/rpcgen/datatype.cpp b/rpcgen/datatype.cpp
index e38cff5..e612799 100644
--- a/rpcgen/datatype.cpp
+++ b/rpcgen/datatype.cpp
@@ -108,7 +108,7 @@ void CDataType::WriteRecvPar(FILE *f)
 	if (retByteCount)
 	{
 		if (IsReturn())
-			fprintf(f, "\t%s rpc_par0 = msg.Get_%s();\n", GetCTypeName(), GetTypeName());
+			fprintf(f, "\trpc_par0 = msg.Get_%s();\n", GetTypeName());
 		else
 			fprintf(f, "\trpc_par%u = msg.Get_%s();\n", id, GetTypeName());
 	}
diff --git a/rpcgen/rpcgen.cpp b/rpcgen/rpcgen.cpp
index f626e3c..1309942 100644
--- a/rpcgen/rpcgen.cpp
+++ b/rpcgen/rpcgen.cpp
@@ -162,7 +162,7 @@ void GenerateServerCodeTrailer(functList &fl, FILE *f)
 
 void GenerateClientEntry(FILE *f, unsigned int cmd, const char *fname, const char *parameter)
 {
-	string cmdId = string("rpc__") + fname + "$" + parameter;
+//	string cmdName = string(fname) + "$" + parameter;
 
 	// read parameter list
 	CParameterList plist;
@@ -170,7 +170,11 @@ void GenerateClientEntry(FILE *f, unsigned int cmd, const char *fname, const cha
 
 	plist.WriteCDeclaration(f, fname);
 	fprintf(f,
-		"{ RPC_PROFILING\n"
+		"{ RPC_PROFILING\n");
+	if (plist.begin()->HasRetValue())
+		fprintf(f, "\t%s rpc_par0;\n", plist.begin()->GetCTypeName());
+	fprintf(f,
+		"\ttry {\n"
 		"\tuint16_t rpc_clientCallId = rpc_GetCallId(%u);\n"
 		"\tRPC_THREAD_LOCK\n"
 		"\trpcMessage msg;\n"
@@ -192,6 +196,7 @@ void GenerateClientEntry(FILE *f, unsigned int cmd, const char *fname, const cha
 		plist.WriteAllRecvDat(f);
 	}
 	fprintf(f, "\tRPC_THREAD_UNLOCK\n");
+	fprintf(f, "\t} catch (CRpcError &e) { e.SetFunction(%u); throw; };\n", cmd);
 	if (plist.begin()->HasRetValue())
 		fputs("\treturn rpc_par0;\n", f);
 	fputs("}\n\n", f);
diff --git a/test_dig.cpp b/test_dig.cpp
index 22ed21f..4cf1a4f 100644
--- a/test_dig.cpp
+++ b/test_dig.cpp
@@ -825,7 +825,7 @@ void test_pulseheight()
 	tb.Daq_Stop();
 	tb.Daq_Read(data, 4000);
 	tb.Daq_Close();
-	DumpData(data, 200);
+//	DumpData(data, 200);
 
 	// --- plot data
 	PixelReadoutData pix;
diff --git a/usb.cpp b/usb.cpp
index cad0eb9..7f4160e 100644
--- a/usb.cpp
+++ b/usb.cpp
@@ -130,7 +130,7 @@ void CUSB::Flush()
 	ftStatus = FT_Write(ftHandle, m_bufferW, bytesToWrite, &bytesWritten);
 
 	if (ftStatus != FT_OK) throw CRpcError(CRpcError::WRITE_ERROR);
-	if ((bytesWritten & 0xFFFFFFFF) != bytesToWrite) { ftStatus = FT_IO_ERROR; throw CRpcError(CRpcError::WRITE_ERROR); }
+	if (bytesWritten != bytesToWrite) { ftStatus = FT_IO_ERROR; throw CRpcError(CRpcError::WRITE_ERROR); }
 }