diff --git a/applications/test/externalCoupler/Make/files b/applications/test/externalCoupler/Make/files
deleted file mode 100644
index 0e55c301e2..0000000000
--- a/applications/test/externalCoupler/Make/files
+++ /dev/null
@@ -1,3 +0,0 @@
-Test-externalCoupler.C
-
-EXE = $(FOAM_USER_APPBIN)/Test-externalCoupler
diff --git a/applications/test/externalCoupler/Make/options b/applications/test/externalCoupler/Make/options
deleted file mode 100644
index e2c645cc88..0000000000
--- a/applications/test/externalCoupler/Make/options
+++ /dev/null
@@ -1,7 +0,0 @@
-EXE_INC = \
-    -I$(LIB_SRC)/finiteVolume/lnInclude \
-    -I$(LIB_SRC)/lumpedPointMotion/lnInclude
-
-EXE_LIBS = \
-    -lfiniteVolume \
-    -llumpedPointMotion
diff --git a/applications/test/externalFileCoupler/Make/files b/applications/test/externalFileCoupler/Make/files
new file mode 100644
index 0000000000..1dc8723085
--- /dev/null
+++ b/applications/test/externalFileCoupler/Make/files
@@ -0,0 +1,3 @@
+Test-externalFileCoupler.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-externalFileCoupler
diff --git a/applications/test/externalFileCoupler/Make/options b/applications/test/externalFileCoupler/Make/options
new file mode 100644
index 0000000000..fa15f12452
--- /dev/null
+++ b/applications/test/externalFileCoupler/Make/options
@@ -0,0 +1,5 @@
+EXE_INC = \
+    -I$(LIB_SRC)/finiteVolume/lnInclude
+
+EXE_LIBS = \
+    -lfiniteVolume
diff --git a/applications/test/externalCoupler/Test-externalCoupler.C b/applications/test/externalFileCoupler/Test-externalFileCoupler.C
similarity index 96%
rename from applications/test/externalCoupler/Test-externalCoupler.C
rename to applications/test/externalFileCoupler/Test-externalFileCoupler.C
index 90cd38d07c..3d04076956 100644
--- a/applications/test/externalCoupler/Test-externalCoupler.C
+++ b/applications/test/externalFileCoupler/Test-externalFileCoupler.C
@@ -22,14 +22,14 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Application
-    Test-externalCoupler
+    Test-externalFileCoupler
 
 Description
     Test of master/slave communication etc.
 \*---------------------------------------------------------------------------*/
 
 #include "argList.H"
-#include "externalCoupler.H"
+#include "externalFileCoupler.H"
 
 using namespace Foam;
 
@@ -47,7 +47,7 @@ int main(int argc, char *argv[])
 
     const label maxCount = args.optionLookupOrDefault<label>("max", 1000);
 
-    externalCoupler coupler;
+    externalFileCoupler coupler;
 
     if (args.optionFound("slave"))
     {
diff --git a/applications/utilities/postProcessing/lumped/lumpedPointMovement/lumpedPointMovement.C b/applications/utilities/postProcessing/lumped/lumpedPointMovement/lumpedPointMovement.C
index fdbc810983..f8418cd1de 100644
--- a/applications/utilities/postProcessing/lumped/lumpedPointMovement/lumpedPointMovement.C
+++ b/applications/utilities/postProcessing/lumped/lumpedPointMovement/lumpedPointMovement.C
@@ -29,7 +29,7 @@ Description
     points/rotations and the corresponding movement of the building surfaces.
     Uses the tabulated responses from the specified file.
     Optionally, it can also be used to a dummy responder for the
-    externalCoupler logic, which makes it useful as a debugging facility
+    externalFileCoupler logic, which makes it useful as a debugging facility
     as well demonstrating how an external application could communicate
     with the lumpedPointMovement point-patch boundary condition.
 
@@ -131,7 +131,7 @@ int main(int argc, char *argv[])
     {
         Info<< "Running as slave responder" << endl;
 
-        externalCoupler& coupler = movement().coupler();
+        externalFileCoupler& coupler = movement().coupler();
 
         label count = 0;
         for (label index = 0; index < responseTable.size(); index += span)
diff --git a/src/finiteVolume/Make/files b/src/finiteVolume/Make/files
index dea1794a8b..7a4cf10981 100644
--- a/src/finiteVolume/Make/files
+++ b/src/finiteVolume/Make/files
@@ -411,6 +411,9 @@ $(general)/bound/bound.C
 $(general)/CorrectPhi/correctUphiBCs.C
 $(general)/pressureControl/pressureControl.C
 
+coupling = $(general)/coupling
+$(coupling)/externalFileCoupler.C
+
 solutionControl = $(general)/solutionControl
 $(solutionControl)/solutionControl/solutionControl.C
 $(solutionControl)/simpleControl/simpleControl.C
diff --git a/src/lumpedPointMotion/externalCoupler.C b/src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.C
similarity index 75%
rename from src/lumpedPointMotion/externalCoupler.C
rename to src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.C
index d5f5a17464..7d891b058f 100644
--- a/src/lumpedPointMotion/externalCoupler.C
+++ b/src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.C
@@ -23,22 +23,21 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-#include "externalCoupler.H"
+#include "externalFileCoupler.H"
 #include "Pstream.H"
 #include "PstreamReduceOps.H"
 #include "OSspecific.H"
-#include "IFstream.H"
-#include "OFstream.H"
 #include "Switch.H"
+#include <fstream>
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
 namespace Foam
 {
-    defineTypeNameAndDebug(externalCoupler, 0);
+    defineTypeNameAndDebug(externalFileCoupler, 0);
 }
 
-Foam::word Foam::externalCoupler::lockName = "OpenFOAM";
+Foam::word Foam::externalFileCoupler::lockName = "OpenFOAM";
 
 
 // file-scope
@@ -46,30 +45,16 @@ Foam::word Foam::externalCoupler::lockName = "OpenFOAM";
 static bool checkIsDone(const std::string& lck)
 {
     std::string content;
-    std::ifstream is(lck.c_str());
+    std::ifstream is(lck);
     is >> content;
 
     return (content.find("done") != std::string::npos);
 }
 
 
-// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
-
-const Foam::fileName& Foam::externalCoupler::baseDir() const
-{
-    return commsDir_;
-}
-
-
-Foam::fileName Foam::externalCoupler::lockFile() const
-{
-    return resolveFile(lockName + ".lock");
-}
-
-
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
-Foam::externalCoupler::externalCoupler()
+Foam::externalFileCoupler::externalFileCoupler()
 :
     runState_(NONE),
     commsDir_("$FOAM_CASE/comms"),
@@ -83,22 +68,41 @@ Foam::externalCoupler::externalCoupler()
 }
 
 
-Foam::externalCoupler::externalCoupler(const dictionary& dict)
+Foam::externalFileCoupler::externalFileCoupler(const fileName& commsDir)
 :
-    externalCoupler()
+    runState_(NONE),
+    commsDir_(commsDir),
+    waitInterval_(1u),
+    timeOut_(100u),
+    slaveFirst_(false),
+    log(false)
+{
+    commsDir_.expand();
+    commsDir_.clean();
+
+    if (Pstream::master())
+    {
+        mkDir(commsDir_);
+    }
+}
+
+
+Foam::externalFileCoupler::externalFileCoupler(const dictionary& dict)
+:
+    externalFileCoupler()
 {
     readDict(dict);
 
     if (Pstream::master())
     {
-        mkDir(baseDir());
+        mkDir(commsDir_);
     }
 }
 
 
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
-Foam::externalCoupler::~externalCoupler()
+Foam::externalFileCoupler::~externalFileCoupler()
 {
     shutdown();
 }
@@ -106,14 +110,21 @@ Foam::externalCoupler::~externalCoupler()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-bool Foam::externalCoupler::readDict(const dictionary& dict)
+bool Foam::externalFileCoupler::readDict(const dictionary& dict)
 {
     // Normally cannot change directory or initialization
     // if things have already been initialized
-    dict.lookup("commsDir") >> commsDir_;
-    commsDir_.expand();
-    commsDir_.clean();
-    slaveFirst_ = dict.lookupOrDefault<bool>("initByExternal", false);
+    if (!initialized())
+    {
+        dict.lookup("commsDir") >> commsDir_;
+        commsDir_.expand();
+        commsDir_.clean();
+        slaveFirst_ = dict.lookupOrDefault<bool>("initByExternal", false);
+
+        Info<< type() << ": initialize" << nl
+            << "    directory: " << commsDir_ << nl
+            << "    slave-first: " << Switch(slaveFirst_) << endl;
+    }
 
     waitInterval_ = dict.lookupOrDefault("waitInterval", 1u);
     if (!waitInterval_)
@@ -130,19 +141,7 @@ bool Foam::externalCoupler::readDict(const dictionary& dict)
 }
 
 
-bool Foam::externalCoupler::initialized() const
-{
-    return runState_ != NONE;
-}
-
-
-bool Foam::externalCoupler::slaveFirst() const
-{
-    return slaveFirst_;
-}
-
-
-void Foam::externalCoupler::useMaster(const bool wait) const
+void Foam::externalFileCoupler::useMaster(const bool wait) const
 {
     const bool wasInit = initialized();
     runState_ = MASTER;
@@ -162,7 +161,7 @@ void Foam::externalCoupler::useMaster(const bool wait) const
         {
             Log << type() << ": creating lock file" << endl;
 
-            OFstream os(lck);
+            std::ofstream os(lck);
             os << "status=openfoam\n";
             os.flush();
         }
@@ -175,7 +174,7 @@ void Foam::externalCoupler::useMaster(const bool wait) const
 }
 
 
-void Foam::externalCoupler::useSlave(const bool wait) const
+void Foam::externalFileCoupler::useSlave(const bool wait) const
 {
     const bool wasInit = initialized();
     runState_ = SLAVE;
@@ -200,7 +199,7 @@ void Foam::externalCoupler::useSlave(const bool wait) const
 }
 
 
-bool Foam::externalCoupler::waitForMaster() const
+bool Foam::externalFileCoupler::waitForMaster() const
 {
     if (!initialized())
     {
@@ -212,7 +211,7 @@ bool Foam::externalCoupler::waitForMaster() const
     {
         const fileName lck(lockFile());
 
-        double prevTime = -1;
+        double prevTime = 0;
         double modTime = 0;
 
         // Wait until file disappears (modTime == 0)
@@ -239,7 +238,7 @@ bool Foam::externalCoupler::waitForMaster() const
 }
 
 
-bool Foam::externalCoupler::waitForSlave() const
+bool Foam::externalFileCoupler::waitForSlave() const
 {
     if (!initialized())
     {
@@ -281,23 +280,38 @@ bool Foam::externalCoupler::waitForSlave() const
 }
 
 
-Foam::fileName Foam::externalCoupler::resolveFile
-(
-    const word& file
-) const
-{
-    return fileName(baseDir()/file);
-}
+void Foam::externalFileCoupler::readDataMaster()
+{}
 
 
-void Foam::externalCoupler::shutdown() const
+void Foam::externalFileCoupler::readDataSlave()
+{}
+
+
+void Foam::externalFileCoupler::writeDataMaster() const
+{}
+
+
+void Foam::externalFileCoupler::writeDataSlave() const
+{}
+
+
+void Foam::externalFileCoupler::removeDataMaster() const
+{}
+
+
+void Foam::externalFileCoupler::removeDataSlave() const
+{}
+
+
+void Foam::externalFileCoupler::shutdown() const
 {
     if (Pstream::master() && runState_ == MASTER && Foam::isDir(commsDir_))
     {
         const fileName lck(lockFile());
 
         Log << type() << ": lock file status=done" << endl;
-        OFstream os(lck);
+        std::ofstream os(lck);
         os  << "status=done\n";
         os.flush();
     }
diff --git a/src/lumpedPointMotion/externalCoupler.H b/src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.H
similarity index 60%
rename from src/lumpedPointMotion/externalCoupler.H
rename to src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.H
index 567bb75adf..7979a784e1 100644
--- a/src/lumpedPointMotion/externalCoupler.H
+++ b/src/finiteVolume/cfdTools/general/coupling/externalFileCoupler.H
@@ -22,7 +22,7 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Class
-    Foam::externalCoupler
+    Foam::externalFileCoupler
 
 Description
     Encapsulates the logic for coordinating between OpenFOAM and an
@@ -57,13 +57,32 @@ Description
     }
     \endverbatim
 
+    A typical coupling loop would look like this (on the master-side):
+    \verbatim
+        initialize - master takes control
+        write data for slave
+        use slave, wait for slave
+        cleanup old data from master
+        read data from slave
+        use master
+    \endverbatim
+
+    On the slave-side:
+    \verbatim
+        wait for master
+        read data from master
+        write data for master
+        use master
+    \endverbatim
+
 SourceFiles
-    externalCoupler.C
+    externalFileCoupler.C
+    externalFileCouplerI.H
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef externalCoupler_H
-#define externalCoupler_H
+#ifndef externalFileCoupler_H
+#define externalFileCoupler_H
 
 #include "fileName.H"
 #include "dictionary.H"
@@ -74,20 +93,26 @@ namespace Foam
 {
 
 /*---------------------------------------------------------------------------*\
-                       Class externalCoupler Declaration
+                     Class externalFileCoupler Declaration
 \*---------------------------------------------------------------------------*/
 
-class externalCoupler
+class externalFileCoupler
 {
-    //- The run state (ie, who is currently in charge)
-    enum runState
-    {
-        NONE,       //!< Not initialized
-        MASTER,     //!< The master (OpenFOAM) is in charge
-        SLAVE,      //!< The slave (external program) is in charge
-        DONE        //!< Finished
-    };
+public:
 
+    // Public data types
+
+        //- The run state (ie, who is currently in charge)
+        enum runState
+        {
+            NONE,       //!< Not initialized
+            MASTER,     //!< The master (OpenFOAM) is in charge
+            SLAVE,      //!< The slave (external program) is in charge
+            DONE        //!< Finished
+        };
+
+
+private:
 
     // Private data
 
@@ -103,7 +128,7 @@ class externalCoupler
         //- Timeout [s] while waiting for the external application
         unsigned timeOut_;
 
-        //- Flag to indicate values are initialized by external application
+        //- Flag to indicate values are initialized by external program
         bool slaveFirst_;
 
         //- Local logging/verbosity flag
@@ -112,22 +137,17 @@ class externalCoupler
 
     // Private Member Functions
 
-        //- Return the file path to the base communications directory
-        const fileName& baseDir() const;
-
-        //- Return the file path to the lock file
-        fileName lockFile() const;
-
-        //- Disallow default bitwise copy construc
-        externalCoupler(const externalCoupler&) = delete;
+        //- Disallow default bitwise copy construct
+        externalFileCoupler(const externalFileCoupler&) = delete;
 
         //- Disallow default bitwise assignmen
-        void operator=(const externalCoupler&) = delete;
+        void operator=(const externalFileCoupler&) = delete;
+
 
 public:
 
     //- Runtime type information
-    TypeName("externalCoupler");
+    TypeName("externalFileCoupler");
 
 
     // Static data members
@@ -138,48 +158,98 @@ public:
 
     // Constructors
 
-        //- Construct null using standard defaults
-        externalCoupler();
+        //- Construct using standard defaults.
+        //  Does not create communications directory.
+        externalFileCoupler();
+
+        //- Construct with specified communications directory.
+        //  Creates the communications directory upon construction.
+        externalFileCoupler(const fileName& commsDir);
 
         //- Construct from dictionary
-        externalCoupler(const dictionary& dict);
+        //  Creates the communications directory upon construction.
+        externalFileCoupler(const dictionary& dict);
 
 
     //- Destructor
-    virtual ~externalCoupler();
+    virtual ~externalFileCoupler();
 
 
     // Member Functions
 
-      // Access
+      // Initialization
 
         //- True if state has been initialized
-        bool initialized() const;
+        inline bool initialized() const;
 
         //- External application provides initial values
-        bool slaveFirst() const;
+        inline bool slaveFirst() const;
+
+
+      // File locations
+
+        //- Return the file path to the base communications directory
+        inline const fileName& commDirectory() const;
+
+        //- Return the file path in the communications directory
+        inline fileName resolveFile(const word& file) const;
+
+        //- Return the file path to the lock file
+        inline fileName lockFile() const;
+
+
+      // Settings
+
+        //- Read communication settings from dictionary
+        bool readDict(const dictionary& dict);
+
+
+      // Handshaking
 
         //- Create lock file to indicate that OpenFOAM is in charge
-        //  Optionally wait for master as well.
+        //  Optionally wait for master to complete as well.
         void useMaster(const bool wait=false) const;
 
-        //- Wait for indication that OpenFOAM has supplied output.
-        //  This is when the lock file disappears, or it exists but with
+        //- Remove lock file to indicate that the external program is in charge
+        //  Optionally wait for slave to complete as well.
+        void useSlave(const bool wait=false) const;
+
+
+        //- Wait for master to complete.
+        //  This is when the lock file disappears, or exists but has
         //  "status=done" content.
         //  \return False if lock file contains "status=done"
         bool waitForMaster() const;
 
-        //- Remove lock file to indicate that the external program is in charge
-        //  Optionally wait for slave as well.
-        void useSlave(const bool wait=false) const;
-
-        //- Wait for indication that the external program has supplied input.
+        //- Wait for slave to complete.
         //  This is when the lock file appears.
         //  \return False if lock file contains "status=done"
         bool waitForSlave() const;
 
-        //- Return the file path in the communications directory
-        fileName resolveFile(const word& file) const;
+
+      // File creation, removal
+
+        //- Read data files on master (OpenFOAM).
+        //  These data files are normally created by the slave.
+        virtual void readDataMaster();
+
+        //- Read data files on slave (external program).
+        //  These data files are normally created by the master.
+        virtual void readDataSlave();
+
+
+        //- Write data files from master (OpenFOAM)
+        virtual void writeDataMaster() const;
+
+        //- Write data files from slave (external program)
+        virtual void writeDataSlave() const;
+
+
+        //- Remove data files written by master (OpenFOAM)
+        virtual void removeDataMaster() const;
+
+        //- Remove data files written by slave (external program)
+        virtual void removeDataSlave() const;
 
         //- Generate status=done in lock (only when run-state = master)
         void shutdown() const;
@@ -188,11 +258,6 @@ public:
         void removeDirectory() const;
 
 
-      // Edit
-
-        //- Read communication settings from dictionary
-        bool readDict(const dictionary& dict);
-
 };
 
 
@@ -202,6 +267,10 @@ public:
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
+#include "externalFileCouplerI.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
 #endif
 
 // ************************************************************************* //
diff --git a/src/finiteVolume/cfdTools/general/coupling/externalFileCouplerI.H b/src/finiteVolume/cfdTools/general/coupling/externalFileCouplerI.H
new file mode 100644
index 0000000000..82f96e3c2e
--- /dev/null
+++ b/src/finiteVolume/cfdTools/general/coupling/externalFileCouplerI.H
@@ -0,0 +1,61 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+inline bool Foam::externalFileCoupler::initialized() const
+{
+    return runState_ != NONE;
+}
+
+
+inline bool Foam::externalFileCoupler::slaveFirst() const
+{
+    return slaveFirst_;
+}
+
+
+inline const Foam::fileName& Foam::externalFileCoupler::commDirectory() const
+{
+    return commsDir_;
+}
+
+
+inline Foam::fileName Foam::externalFileCoupler::resolveFile
+(
+    const word& file
+) const
+{
+    return fileName(commDirectory()/file);
+}
+
+
+inline Foam::fileName Foam::externalFileCoupler::lockFile() const
+{
+    return resolveFile(lockName + ".lock");
+}
+
+
+// ************************************************************************* //
diff --git a/src/functionObjects/field/externalCoupled/externalCoupled.C b/src/functionObjects/field/externalCoupled/externalCoupled.C
index 80ef9247da..96871a02cf 100644
--- a/src/functionObjects/field/externalCoupled/externalCoupled.C
+++ b/src/functionObjects/field/externalCoupled/externalCoupled.C
@@ -50,20 +50,6 @@ namespace functionObjects
 }
 }
 
-const Foam::Enum
-<
-    Foam::functionObjects::externalCoupled::stateEnd
->
-Foam::functionObjects::externalCoupled::stateEndNames_
-{
-    { stateEnd::REMOVE, "remove" },
-    { stateEnd::DONE, "done" }
-    // 'IGNORE' is internal use only and thus without a name
-};
-
-
-Foam::word Foam::functionObjects::externalCoupled::lockName = "OpenFOAM";
-
 Foam::string Foam::functionObjects::externalCoupled::patchKey = "// Patch:";
 
 
@@ -99,15 +85,6 @@ static void writeList(Ostream& os, const string& header, const UList<T>& L)
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-Foam::fileName Foam::functionObjects::externalCoupled::baseDir() const
-{
-    fileName result(commsDir_);
-    result.clean();
-
-    return result;
-}
-
-
 Foam::fileName Foam::functionObjects::externalCoupled::groupDir
 (
     const fileName& commsDir,
@@ -127,171 +104,6 @@ Foam::fileName Foam::functionObjects::externalCoupled::groupDir
 }
 
 
-Foam::fileName Foam::functionObjects::externalCoupled::lockFile() const
-{
-    return fileName(baseDir()/(lockName + ".lock"));
-}
-
-
-void Foam::functionObjects::externalCoupled::useMaster() const
-{
-    if (Pstream::master())
-    {
-        const fileName lck(lockFile());
-
-        // Only create lock file if it doesn't already exist
-        if (!Foam::isFile(lck))
-        {
-            Log << type() << ": creating lock file" << endl;
-
-            OFstream os(lck);
-            os << "status=openfoam\n";
-            os.flush();
-        }
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::useSlave() const
-{
-    if (Pstream::master())
-    {
-        Log << type() << ": removing lock file" << endl;
-
-        Foam::rm(lockFile());
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::cleanup() const
-{
-    if (Pstream::master())
-    {
-        const fileName lck(lockFile());
-        switch (stateEnd_)
-        {
-            case REMOVE:
-            {
-                Log << type() << ": removing lock file" << endl;
-                Foam::rm(lck);
-                break;
-            }
-            case DONE:
-            {
-                Log << type() << ": lock file status=done" << endl;
-                OFstream os(lck);
-                os  << "status=done\n";
-                os.flush();
-                break;
-            }
-            case IGNORE:
-                break;
-        }
-
-        stateEnd_ = IGNORE;   // Avoid re-triggering in destructor
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::removeDataSlave() const
-{
-    if (!Pstream::master())
-    {
-        return;
-    }
-
-    Log << type() << ": removing data files written by slave" << nl;
-
-    forAll(regionGroupNames_, regioni)
-    {
-        const word& compName = regionGroupNames_[regioni];
-
-        const labelList& groups = regionToGroups_[compName];
-        forAll(groups, i)
-        {
-            label groupi = groups[i];
-            const wordRe& groupName = groupNames_[groupi];
-
-            forAll(groupReadFields_[groupi], fieldi)
-            {
-                const word& fieldName = groupReadFields_[groupi][fieldi];
-                rm
-                (
-                    groupDir(commsDir_, compName, groupName)
-                  / fieldName + ".in"
-                );
-            }
-        }
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::removeDataMaster() const
-{
-    if (!Pstream::master())
-    {
-        return;
-    }
-
-    Log << type() << ": removing data files written by master" << nl;
-
-    forAll(regionGroupNames_, regioni)
-    {
-        const word& compName = regionGroupNames_[regioni];
-
-        const labelList& groups = regionToGroups_[compName];
-        forAll(groups, i)
-        {
-            label groupi = groups[i];
-            const wordRe& groupName = groupNames_[groupi];
-
-            forAll(groupReadFields_[groupi], fieldi)
-            {
-                const word& fieldName = groupReadFields_[groupi][fieldi];
-                rm
-                (
-                    groupDir(commsDir_, compName, groupName)
-                  / fieldName + ".out"
-                );
-            }
-        }
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::waitForSlave() const
-{
-    bool waiting = true;
-    if (Pstream::master())
-    {
-        const fileName lck(lockFile());
-        unsigned totalTime = 0;
-
-        Log << type() << ": beginning wait for lock file " << lck << nl;
-
-        while ((waiting = !Foam::isFile(lck)) == true)
-        {
-            sleep(waitInterval_);
-            totalTime += waitInterval_;
-
-            if (timeOut_ && totalTime > timeOut_)
-            {
-                FatalErrorInFunction
-                    << "Wait time exceeded timeout of " << timeOut_
-                    << " s" << abort(FatalError);
-            }
-
-            Log << type() << ": wait time = " << totalTime << endl;
-        }
-
-        Log << type() << ": found lock file " << lck << endl;
-    }
-
-    // MPI barrier
-    Pstream::scatter(waiting);
-}
-
-
 void Foam::functionObjects::externalCoupled::readColumns
 (
     const label nRows,
@@ -592,155 +404,9 @@ void Foam::functionObjects::externalCoupled::checkOrder
 }
 
 
-void Foam::functionObjects::externalCoupled::readData()
+void Foam::functionObjects::externalCoupled::initCoupling()
 {
-    forAll(regionGroupNames_, regioni)
-    {
-        const word& compName = regionGroupNames_[regioni];
-        const wordList& regionNames = regionGroupRegions_[regioni];
-
-        // Get the meshes for the region-group
-        UPtrList<const fvMesh> meshes(regionNames.size());
-        forAll(regionNames, j)
-        {
-            const word& regionName = regionNames[j];
-            meshes.set(j, &time_.lookupObject<fvMesh>(regionName));
-        }
-
-        const labelList& groups = regionToGroups_[compName];
-
-        forAll(groups, i)
-        {
-            label groupi = groups[i];
-            const wordRe& groupName = groupNames_[groupi];
-            const wordList& fieldNames = groupReadFields_[groupi];
-
-            forAll(fieldNames, fieldi)
-            {
-                const word& fieldName = fieldNames[fieldi];
-
-                const bool ok =
-                (
-                    readData<scalar>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || readData<vector>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || readData<sphericalTensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || readData<symmTensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || readData<tensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                );
-
-                if (!ok)
-                {
-                    WarningInFunction
-                        << "Field " << fieldName << " in regions " << compName
-                        << " was not found." << endl;
-                }
-            }
-        }
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::writeData() const
-{
-    forAll(regionGroupNames_, regioni)
-    {
-        const word& compName = regionGroupNames_[regioni];
-        const wordList& regionNames = regionGroupRegions_[regioni];
-
-        // Get the meshes for the region-group
-        UPtrList<const fvMesh> meshes(regionNames.size());
-        forAll(regionNames, j)
-        {
-            const word& regionName = regionNames[j];
-            meshes.set(j, &time_.lookupObject<fvMesh>(regionName));
-        }
-
-        const labelList& groups = regionToGroups_[compName];
-
-        forAll(groups, i)
-        {
-            label groupi = groups[i];
-            const wordRe& groupName = groupNames_[groupi];
-            const wordList& fieldNames = groupWriteFields_[groupi];
-
-            forAll(fieldNames, fieldi)
-            {
-                const word& fieldName = fieldNames[fieldi];
-
-                const bool ok =
-                (
-                    writeData<scalar>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || writeData<vector>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || writeData<sphericalTensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || writeData<symmTensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                 || writeData<tensor>
-                    (
-                        meshes,
-                        groupName,
-                        fieldName
-                    )
-                );
-
-                if (!ok)
-                {
-                    WarningInFunction
-                        << "Field " << fieldName << " in regions " << compName
-                        << " was not found." << endl;
-                }
-            }
-        }
-    }
-}
-
-
-void Foam::functionObjects::externalCoupled::initialise()
-{
-    if (initialised_)
+    if (initialisedCoupling_)
     {
         return;
     }
@@ -769,7 +435,7 @@ void Foam::functionObjects::externalCoupled::initialise()
             bool exists = false;
             if (Pstream::master())
             {
-                fileName dir(groupDir(commsDir_, compName, groupName));
+                fileName dir(groupDir(commDirectory(), compName, groupName));
 
                 exists =
                     isFile(dir/"patchPoints")
@@ -778,21 +444,21 @@ void Foam::functionObjects::externalCoupled::initialise()
 
             if (!returnReduce(exists, orOp<bool>()))
             {
-                writeGeometry(meshes, commsDir_, groupName);
+                writeGeometry(meshes, commDirectory(), groupName);
             }
         }
     }
 
-    if (slaveFirst_)
+    if (slaveFirst())
     {
         // Wait for initial data to be made available
         waitForSlave();
 
         // Read data passed back from external source
-        readData();
+        readDataMaster();
     }
 
-    initialised_ = true;
+    initialisedCoupling_ = true;
 }
 
 
@@ -806,18 +472,13 @@ Foam::functionObjects::externalCoupled::externalCoupled
 )
 :
     functionObject(name),
+    externalFileCoupler(),
     time_(runTime),
-    stateEnd_(REMOVE),
-    initialised_(false)
+    initialisedCoupling_(false)
 {
     read(dict);
 
-    if (Pstream::master())
-    {
-        mkDir(baseDir());
-    }
-
-    if (!slaveFirst_)
+    if (!slaveFirst())
     {
         useMaster();
     }
@@ -827,22 +488,20 @@ Foam::functionObjects::externalCoupled::externalCoupled
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
 Foam::functionObjects::externalCoupled::~externalCoupled()
-{
-    cleanup();
-}
+{}
 
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 bool Foam::functionObjects::externalCoupled::execute()
 {
-    if (!initialised_ || time_.timeIndex() % calcFrequency_ == 0)
+    if (!initialisedCoupling_ || time_.timeIndex() % calcFrequency_ == 0)
     {
         // Initialise the coupling
-        initialise();
+        initCoupling();
 
         // Write data for external source
-        writeData();
+        writeDataMaster();
 
         // Signal external source to execute (by removing lock file)
         // - Wait for slave to provide data
@@ -855,7 +514,7 @@ bool Foam::functionObjects::externalCoupled::execute()
         removeDataMaster();
 
         // Read data passed back from external source
-        readData();
+        readDataMaster();
 
         // Signal external source to wait (by creating the lock file)
         useMaster();
@@ -876,7 +535,7 @@ bool Foam::functionObjects::externalCoupled::end()
     // Remove old data files
     removeDataMaster();
     removeDataSlave();
-    cleanup();
+    shutdown();
 
     return true;
 }
@@ -885,33 +544,10 @@ bool Foam::functionObjects::externalCoupled::end()
 bool Foam::functionObjects::externalCoupled::read(const dictionary& dict)
 {
     functionObject::read(dict);
-
-    // NB: Cannot change directory or initialization
-    // if things have already been initialized
-    if (!initialised_)
-    {
-        dict.lookup("commsDir") >> commsDir_;
-        commsDir_.expand();
-        commsDir_.clean();
-
-        slaveFirst_ = readBool(dict.lookup("initByExternal"));
-        // slaveFirst_ = dict.lookupOrDefault<bool>("initByExternal", false);
-    }
+    externalFileCoupler::readDict(dict);
 
     calcFrequency_ = dict.lookupOrDefault("calcFrequency", 1);
 
-    waitInterval_ = dict.lookupOrDefault("waitInterval", 1u);
-    if (!waitInterval_)
-    {
-        // Enforce non-zero sleep
-        waitInterval_ = 1u;
-    }
-
-    timeOut_ = dict.lookupOrDefault("timeOut", 100*waitInterval_);
-    stateEnd_ =
-        stateEndNames_.lookupOrDefault("stateEnd", dict, stateEnd::DONE);
-
-
     // Get names of all fvMeshes (and derived types)
     wordList allRegionNames(time_.lookupClass<fvMesh>().sortedToc());
 
@@ -1013,7 +649,8 @@ bool Foam::functionObjects::externalCoupled::read(const dictionary& dict)
                 label groupi = groups[i];
                 const wordRe& groupName = groupNames_[groupi];
 
-                fileName dir(groupDir(commsDir_, compName, groupName));
+                fileName dir(groupDir(commDirectory(), compName, groupName));
+
                 if (!isDir(dir))
                 {
                     Log << type() << ": creating communications directory "
@@ -1028,6 +665,218 @@ bool Foam::functionObjects::externalCoupled::read(const dictionary& dict)
 }
 
 
+void Foam::functionObjects::externalCoupled::readDataMaster()
+{
+    forAll(regionGroupNames_, regioni)
+    {
+        const word& compName = regionGroupNames_[regioni];
+        const wordList& regionNames = regionGroupRegions_[regioni];
+
+        // Get the meshes for the region-group
+        UPtrList<const fvMesh> meshes(regionNames.size());
+        forAll(regionNames, j)
+        {
+            const word& regionName = regionNames[j];
+            meshes.set(j, &time_.lookupObject<fvMesh>(regionName));
+        }
+
+        const labelList& groups = regionToGroups_[compName];
+
+        forAll(groups, i)
+        {
+            label groupi = groups[i];
+            const wordRe& groupName = groupNames_[groupi];
+            const wordList& fieldNames = groupReadFields_[groupi];
+
+            forAll(fieldNames, fieldi)
+            {
+                const word& fieldName = fieldNames[fieldi];
+
+                const bool ok =
+                (
+                    readData<scalar>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || readData<vector>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || readData<sphericalTensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || readData<symmTensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || readData<tensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                );
+
+                if (!ok)
+                {
+                    WarningInFunction
+                        << "Field " << fieldName << " in regions " << compName
+                        << " was not found." << endl;
+                }
+            }
+        }
+    }
+}
+
+
+void Foam::functionObjects::externalCoupled::writeDataMaster() const
+{
+    forAll(regionGroupNames_, regioni)
+    {
+        const word& compName = regionGroupNames_[regioni];
+        const wordList& regionNames = regionGroupRegions_[regioni];
+
+        // Get the meshes for the region-group
+        UPtrList<const fvMesh> meshes(regionNames.size());
+        forAll(regionNames, j)
+        {
+            const word& regionName = regionNames[j];
+            meshes.set(j, &time_.lookupObject<fvMesh>(regionName));
+        }
+
+        const labelList& groups = regionToGroups_[compName];
+
+        forAll(groups, i)
+        {
+            label groupi = groups[i];
+            const wordRe& groupName = groupNames_[groupi];
+            const wordList& fieldNames = groupWriteFields_[groupi];
+
+            forAll(fieldNames, fieldi)
+            {
+                const word& fieldName = fieldNames[fieldi];
+
+                const bool ok =
+                (
+                    writeData<scalar>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || writeData<vector>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || writeData<sphericalTensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || writeData<symmTensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                 || writeData<tensor>
+                    (
+                        meshes,
+                        groupName,
+                        fieldName
+                    )
+                );
+
+                if (!ok)
+                {
+                    WarningInFunction
+                        << "Field " << fieldName << " in regions " << compName
+                        << " was not found." << endl;
+                }
+            }
+        }
+    }
+}
+
+
+void Foam::functionObjects::externalCoupled::removeDataMaster() const
+{
+    if (!Pstream::master())
+    {
+        return;
+    }
+
+    Log << type() << ": removing data files written by master" << nl;
+
+    forAll(regionGroupNames_, regioni)
+    {
+        const word& compName = regionGroupNames_[regioni];
+
+        const labelList& groups = regionToGroups_[compName];
+        forAll(groups, i)
+        {
+            label groupi = groups[i];
+            const wordRe& groupName = groupNames_[groupi];
+
+            forAll(groupReadFields_[groupi], fieldi)
+            {
+                const word& fieldName = groupReadFields_[groupi][fieldi];
+                rm
+                (
+                    groupDir(commDirectory(), compName, groupName)
+                  / fieldName + ".out"
+                );
+            }
+        }
+    }
+}
+
+
+void Foam::functionObjects::externalCoupled::removeDataSlave() const
+{
+    if (!Pstream::master())
+    {
+        return;
+    }
+
+    Log << type() << ": removing data files written by slave" << nl;
+
+    forAll(regionGroupNames_, regioni)
+    {
+        const word& compName = regionGroupNames_[regioni];
+
+        const labelList& groups = regionToGroups_[compName];
+        forAll(groups, i)
+        {
+            label groupi = groups[i];
+            const wordRe& groupName = groupNames_[groupi];
+
+            forAll(groupReadFields_[groupi], fieldi)
+            {
+                const word& fieldName = groupReadFields_[groupi][fieldi];
+                rm
+                (
+                    groupDir(commDirectory(), compName, groupName)
+                  / fieldName + ".in"
+                );
+            }
+        }
+    }
+}
+
+
 bool Foam::functionObjects::externalCoupled::write()
 {
     return true;
diff --git a/src/functionObjects/field/externalCoupled/externalCoupled.H b/src/functionObjects/field/externalCoupled/externalCoupled.H
index 52696eb48f..e0059d9bf1 100644
--- a/src/functionObjects/field/externalCoupled/externalCoupled.H
+++ b/src/functionObjects/field/externalCoupled/externalCoupled.H
@@ -42,7 +42,7 @@ Description
 
     where the actual entries depend on the bc type:
     - mixed: value, snGrad, refValue, refGrad, valueFraction
-    - externalCoupledMixed: output of writeData
+    - externalCoupledMixed: output of writeDataMaster
     - other: value, snGrad
 
     These text files are located in a user specified communications directory
@@ -146,6 +146,7 @@ SourceFiles
 #define functionObjects_externalCoupled_H
 
 #include "functionObject.H"
+#include "externalFileCoupler.H"
 #include "DynamicList.H"
 #include "wordReList.H"
 #include "scalarField.H"
@@ -171,7 +172,8 @@ namespace functionObjects
 
 class externalCoupled
 :
-    public functionObject
+    public functionObject,
+    public externalFileCoupler
 {
 public:
 
@@ -190,30 +192,14 @@ private:
         //- State end names (NB, only selectable values itemized)
         static const Enum<stateEnd> stateEndNames_;
 
-
     // Private data
 
         //- Reference to the time database
         const Time& time_;
 
-        //- Path to communications directory
-        fileName commsDir_;
-
-        //- Interval time between checking for return data [s]
-        unsigned waitInterval_;
-
-        //- Time out time [s]
-        unsigned timeOut_;
-
         //- Calculation frequency
         label calcFrequency_;
 
-        //- Flag to indicate values are initialised by external application
-        bool slaveFirst_;
-
-        //- Lockfile state on termination
-        mutable stateEnd stateEnd_;
-
         //- Names of (composite) regions
         DynamicList<word> regionGroupNames_;
 
@@ -232,8 +218,8 @@ private:
         // Per group the names of the fields to write
         DynamicList<wordList> groupWriteFields_;
 
-        //- Initialised flag
-        bool initialised_;
+        //- Initialised coupling
+        bool initialisedCoupling_;
 
 
     // Private Member Functions
@@ -246,32 +232,6 @@ private:
             const wordRe& groupName
         );
 
-        //- Return the file path to the base communications directory
-        fileName baseDir() const;
-
-        //- Return the file path to the lock file
-        fileName lockFile() const;
-
-
-        //- Create lock file to indicate that OpenFOAM is in charge
-        void useMaster() const;
-
-        //- Remove lock file to indicate that the external program is in charge
-        void useSlave() const;
-
-        //- Remove lock file or status=done in lock.
-        void cleanup() const;
-
-        //- Remove files written by OpenFOAM
-        void removeDataMaster() const;
-
-        //- Remove files written by external code
-        void removeDataSlave() const;
-
-        //- Wait for indication that the external program has supplied input
-        //  (ie, for the lock file to reappear).
-        void waitForSlave() const;
-
 
         //- Read data for a single region, single field
         template<class Type>
@@ -281,8 +241,6 @@ private:
             const wordRe& groupName,
             const word& fieldName
         );
-        //- Read data for all regions, all fields
-        void readData();
 
         //- Write data for a single region, single field
         template<class Type>
@@ -293,10 +251,7 @@ private:
             const word& fieldName
         ) const;
 
-        //- Write data for all regions, all fields
-        void writeData() const;
-
-        void initialise();
+        void initCoupling();
 
         //- Read (and distribute) scalar columns from stream. Every processor
         //  gets nRows (= patch size) of these. Note: could make its argument
@@ -339,12 +294,12 @@ public:
     //- Runtime type information
     TypeName("externalCoupled");
 
-    //- Name of lock file (normally 'OpenFOAM.lock')
-    static word lockName;
-
     //- Name of patch key, e.g. '// Patch:' when looking for start of patch data
     static string patchKey;
 
+    //- Inherited variable for logging
+    using functionObject::log;
+
 
     // Constructors
 
@@ -378,6 +333,21 @@ public:
         virtual bool write();
 
 
+      // File creation, removal
+
+        //- Write data files (all regions, all fields) from master (OpenFOAM)
+        virtual void writeDataMaster() const;
+
+        //- Read data files (all regions, all fields) on master (OpenFOAM)
+        virtual void readDataMaster();
+
+        //- Remove data files written by master (OpenFOAM)
+        virtual void removeDataMaster() const;
+
+        //- Remove data files written by slave (external code)
+        virtual void removeDataSlave() const;
+
+
       // Other
 
         //- Create single name by appending words (in sorted order),
diff --git a/src/functionObjects/field/externalCoupled/externalCoupledTemplates.C b/src/functionObjects/field/externalCoupled/externalCoupledTemplates.C
index 84f092836d..ee0bb19de7 100644
--- a/src/functionObjects/field/externalCoupled/externalCoupledTemplates.C
+++ b/src/functionObjects/field/externalCoupled/externalCoupledTemplates.C
@@ -62,7 +62,7 @@ bool Foam::functionObjects::externalCoupled::readData
     {
         const fileName transferFile
         (
-            groupDir(commsDir_, compositeName(regionNames), groupName)
+            groupDir(commDirectory(), compositeName(regionNames), groupName)
           / fieldName + ".in"
         );
 
@@ -280,7 +280,7 @@ bool Foam::functionObjects::externalCoupled::readData
                     << exit(FatalError);
             }
 
-            initialised_ = true;
+            initialisedCoupling_ = true;
         }
     }
 
@@ -357,7 +357,7 @@ bool Foam::functionObjects::externalCoupled::writeData
     {
         const fileName transferFile
         (
-            groupDir(commsDir_, compositeName(regionNames), groupName)
+            groupDir(commDirectory(), compositeName(regionNames), groupName)
           / fieldName + ".out"
         );
 
diff --git a/src/lumpedPointMotion/Make/files b/src/lumpedPointMotion/Make/files
index b525c884b8..e39fbdbdb6 100644
--- a/src/lumpedPointMotion/Make/files
+++ b/src/lumpedPointMotion/Make/files
@@ -1,5 +1,3 @@
-externalCoupler.C
-
 lumpedPointMovement.C
 lumpedPointMovementWriter.C
 lumpedPointState.C
diff --git a/src/lumpedPointMotion/lumpedPointMovement.H b/src/lumpedPointMotion/lumpedPointMovement.H
index 3a6733b127..dc0f1fb189 100644
--- a/src/lumpedPointMotion/lumpedPointMovement.H
+++ b/src/lumpedPointMotion/lumpedPointMovement.H
@@ -50,7 +50,7 @@ SourceFiles
 #include "IOobject.H"
 #include "tmp.H"
 #include "faceZoneMeshFwd.H"
-#include "externalCoupler.H"
+#include "externalFileCoupler.H"
 #include "lumpedPointState.H"
 #include "boundBox.H"
 #include "Enum.H"
@@ -120,7 +120,7 @@ private:
         dictionary forcesDict_;
 
         //- Communication control
-        externalCoupler coupler_;
+        externalFileCoupler coupler_;
 
         //- File io
         word inputName_;
@@ -223,10 +223,10 @@ public:
 
 
         //- Communication control
-        inline const externalCoupler& coupler() const;
+        inline const externalFileCoupler& coupler() const;
 
         //- Communication control
-        inline externalCoupler& coupler();
+        inline externalFileCoupler& coupler();
 
         //- The initial state (positions/rotations)
         inline const lumpedPointState& state0() const;
diff --git a/src/lumpedPointMotion/lumpedPointMovementI.H b/src/lumpedPointMotion/lumpedPointMovementI.H
index 36f189d1a2..43bcdb3094 100644
--- a/src/lumpedPointMotion/lumpedPointMovementI.H
+++ b/src/lumpedPointMotion/lumpedPointMovementI.H
@@ -83,13 +83,14 @@ Foam::lumpedPointMovement::threshold(const point& position) const
 }
 
 
-inline const Foam::externalCoupler& Foam::lumpedPointMovement::coupler() const
+inline const Foam::externalFileCoupler&
+Foam::lumpedPointMovement::coupler() const
 {
     return coupler_;
 }
 
 
-inline Foam::externalCoupler& Foam::lumpedPointMovement::coupler()
+inline Foam::externalFileCoupler& Foam::lumpedPointMovement::coupler()
 {
     return coupler_;
 }
diff --git a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/Allrun b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/Allrun
index 0a12ee44a7..6191f4b7b1 100755
--- a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/Allrun
+++ b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/Allrun
@@ -6,6 +6,9 @@ cd ${0%/*} || exit 1    # Run from this directory
 
 ./Allrun.pre
 
+# Remove lock file on interrupt
+trap '\rm -f comms/OpenFOAM.lock 2>/dev/null' INT
+
 #-- Run on single processor
 #runApplication $(getApplication) &
 # Simulated external solver
diff --git a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/externalSolver b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/externalSolver
index 8aa12c1628..aba9a81143 100755
--- a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/externalSolver
+++ b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/externalSolver
@@ -14,12 +14,11 @@ set -u
 echo "Executing dummy external solver"
 
 commsDir="comms"
-regionGroupName="heater_topAir"
-patchGroupName="coupleGroup"
+patchDir="heater_topAir/coupleGroup"
 fieldName="T"
 
 lockFile="${commsDir}/OpenFOAM.lock"
-dataFile="${commsDir}/${regionGroupName}/${patchGroupName}/${fieldName}"
+dataFile="${commsDir}/${patchDir}/${fieldName}"
 waitSec=5
 timeOut=100
 nSteps=1000 # maximum number of time steps. Note: should be more than
@@ -27,7 +26,6 @@ nSteps=1000 # maximum number of time steps. Note: should be more than
 refGrad=0
 valueFraction=1
 
-
 # Remove any old junk
 \rm -f $lockFile 2>/dev/null
 
@@ -36,36 +34,53 @@ log()
     echo "External: $@"
 }
 
-init()
+
+# Create lock file to pass control to OpenFOAM
+useMaster()
 {
-    log "init - creating ${dataFile}.in"
-
-    # Hard-coded for patch of size 8 (heater/minY)
-    n1=8
-    refValue1=500
-    touch "${dataFile}.in"
-    log "init - adding $n1 data elements with refValue $refValue1"
-    for i in $(seq 1 $n1); do
-        echo "$refValue1 $refGrad $valueFraction" >> "${dataFile}.in"
-    done
-
-    # Hard-coded for patch of size 40 (topAir/minX)
-    n2=40
-    refValue2=300
-    log "init - adding $n2 data elements with refValue $refValue2"
-    for i in $(seq 1 $n2); do
-        echo "$refValue2 $refGrad $valueFraction" >> "${dataFile}.in"
-    done
-
-    # Create lock file to pass control to OpenFOAM
-    touch ${lockFile}
+    log "creating lock file '${lockFile}'"
+    echo "status=openfoam" >| ${lockFile}
 }
 
 
-# create the comms directory
-mkdir -p ${commsDir}/${regionGroupName}/${patchGroupName}
+init()
+{
+    log "init - creating ${dataFile}.in"
+    cat /dev/null >| "${dataFile}.in"
 
-# Tutorial case uses 'initByExternalOption', so we must provide initial values
+    # Hard-coded for patch of size 8 (heater/minY)
+    local n1=8
+    local refValue1=500
+
+    log "init - adding $n1 data elements with refValue $refValue1"
+    for i in $(seq 1 $n1)
+    do
+        echo "$refValue1 $refGrad $valueFraction"
+    done >> "${dataFile}.in"
+
+    # Hard-coded for patch of size 40 (topAir/minX)
+    local n2=40
+    local refValue2=300
+    log "init - adding $n2 data elements with refValue $refValue2"
+    for i in $(seq 1 $n2)
+    do
+        echo "$refValue2 $refGrad $valueFraction"
+    done >> "${dataFile}.in"
+
+    # Verify line count?
+    # log "init ($(wc -l ${dataFile}.in))"
+
+    # Give time for T.in file to flush
+    sleep 1
+
+    useMaster
+}
+
+
+# Create the comms directory
+mkdir -p ${commsDir}/${patchDir}
+
+# Tutorial case uses 'initByExternal' option, so we must provide initial values
 init
 
 
@@ -108,8 +123,7 @@ do
         awk '{if( $1 != "#" ){print $1+1 " 0 1"}}' \
             ${dataFile}.out >| ${dataFile}.in
 
-        log "creating lock file '${lockFile}'"
-        touch ${lockFile}
+        useMaster
     fi
 done
 
diff --git a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/system/externalCoupled b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/system/externalCoupled
index 590ee32970..85e647d696 100644
--- a/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/system/externalCoupled
+++ b/tutorials/heatTransfer/chtMultiRegionFoam/externalCoupledMultiRegionHeater/system/externalCoupled
@@ -14,9 +14,6 @@ externalCoupled
     // Does external process start first
     initByExternal  true;
 
-    // Cleanup behaviour on termination (remove|done)
-    stateEnd        done;
-
     // Additional output
     log             true;