diff --git a/CVReader.ino b/CVReader.ino
index ab3c458..9925386 100644
--- a/CVReader.ino
+++ b/CVReader.ino
@@ -82,9 +82,7 @@ void setup() {
    // Standard supported devices have pre-configured macros but custome hardware installations require 
    //  detailed pin mappings and may also require modified subclasses of the MotorDriver to implement specialist logic.
      
-   DCC::begin(new MotorDriver(MAIN_POWER_PIN,MAIN_SIGNAL_PIN,MAIN_SIGNAL_PIN_ALT,MAIN_BRAKE_PIN,MAIN_SENSE_PIN,MAIN_SENSE_FACTOR, MAIN_MAX_MILLIAMPS,MAIN_FAULT_PIN),
-              new MotorDriver(PROG_POWER_PIN,PROG_SIGNAL_PIN,PROG_SIGNAL_PIN_ALT,PROG_BRAKE_PIN,PROG_SENSE_PIN,PROG_SENSE_FACTOR, PROG_MAX_MILLIAMPS,PROG_FAULT_PIN));
-   
+   DCC::begin(STANDARD_MOTOR_SHIELD);
 
    // Responsibility 3: Optionally Start the WiFi interface if required.
    //   NOTE: On a Uno you will have to provide a SoftwareSerial 
diff --git a/Config.h b/Config.h
index 1a495bc..20705c4 100644
--- a/Config.h
+++ b/Config.h
@@ -1,34 +1,28 @@
 #ifndef Config_h
 #define Config_h
 
+// *** PLEASE NOTE *** THIS FILE IS  **NOT**  INTENDED TO BE EDITED WHEN CONFIGURING A SYSTEM.
+// It will be overwritten if the library is updated.
+
+// This file contains configurations for known/supported motor shields.
+// A configuration defined by macro here can be used in your sketch.
+// A custom hardware setup will require your sketch to create MotorDriver instances
+// similar to those defined here, WITHOUT editing this file.
+   
 // Define these if you have a WiFi board on Serial1
 #define WIFI
 #define WIFI_CONNECT_TO_SSID  "RPi-JMRI"
 #define WIFI_CONNECT_PASSWORD "rpI-jmri"
 
-// This hardware configuration would normally be setup using a bunch of #ifdefs.
-
 const byte UNUSED_PIN = 255;
 
-const byte MAIN_POWER_PIN = 3;
-const byte MAIN_SIGNAL_PIN = 12;
-const byte MAIN_SIGNAL_PIN_ALT = UNUSED_PIN;  // for hardware that flipflops signal pins 
-const byte MAIN_SENSE_PIN = A0;   
-const byte MAIN_BRAKE_PIN = 9;
-const byte MAIN_FAULT_PIN = UNUSED_PIN;
+// MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, byte brake_pin, byte current_pin, float senseFactor, unsigned int tripMilliamps, byte faultPin);
+    
+// Arduino standard Motor Shield
+#define STANDARD_MOTOR_SHIELD     \
+   new MotorDriver(3 , 12, UNUSED_PIN, 9, A0, 2.99, 2000, UNUSED_PIN),    \
+   new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 2.99, 250 , UNUSED_PIN) 
 
-const int   MAIN_MAX_MILLIAMPS=2000;
-const float MAIN_SENSE_FACTOR=2.99; //  analgRead(MAIN_SENSE_PIN) * MAIN_SENSE_FACTOR = milliamps 
-
-const byte PROG_POWER_PIN = 11;
-const byte PROG_SIGNAL_PIN = 13;
-const byte PROG_SIGNAL_PIN_ALT = UNUSED_PIN;  // for hardware that flipflops signal pins 
-const byte PROG_SENSE_PIN = A1;
-const byte PROG_BRAKE_PIN = 8;
-const byte PROG_FAULT_PIN = UNUSED_PIN;
-
-const int   PROG_MAX_MILLIAMPS=250;
-const float PROG_SENSE_FACTOR=2.99; //  analgRead(PROG_SENSE_PIN) * PROG_SENSE_FACTOR = milliamps 
 
 // Allocations with memory implications..!
 // Base system takes approx 900 bytes + 8 per loco. Turnouts, Sensors etc are dynamically created
diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
index 890d33c..03bb776 100644
--- a/DCCWaveform.cpp
+++ b/DCCWaveform.cpp
@@ -26,7 +26,7 @@
 DCCWaveform  DCCWaveform::mainTrack(PREAMBLE_BITS_MAIN, true);
 DCCWaveform  DCCWaveform::progTrack(PREAMBLE_BITS_PROG, false);
 
-const int ACK_MIN_PULSE_RAW=65 / PROG_SENSE_FACTOR;
+//const int ACK_MIN_PULSE_RAW=65 / PROG_SENSE_FACTOR;
 
 bool DCCWaveform::progTrackSyncMain=false; 
 
@@ -265,7 +265,7 @@ int DCCWaveform::getLastCurrent() {
 
 void DCCWaveform::setAckBaseline(bool debug) {
       if (isMainTrack) return; 
-      ackThreshold=motorDriver->getCurrentRaw() + ACK_MIN_PULSE_RAW;
+      ackThreshold=motorDriver->getCurrentRaw() + (int)(65 / motorDriver->senseFactor);
       if (debug) DIAG(F("\nACK-BASELINE %d/%dmA"),ackThreshold,motorDriver->convertToMilliamps(ackThreshold));
 }