Merge pull request #221 from EuropeanSpallationSource/doc-CNEN-HOMF-H…

…OMR-better

Improved CNEN, HOMF & HOMR documentation

docs/motorRecord.html

@@ -2377,7 +2377,13 @@ <h2>Field Descriptions</h2> In addition to fields common to all record types (se
     motor stops, the VAL field will be set equal to the RBV field, and the DVAL 
     field will be set equal to the DRBV field.&nbsp; These fields can be set to 1, 
     but setting either field to 0 results in an error.&nbsp; The record sets HOM[F/R] 
-    to zero when the homing procedure is either completed or aborted.</td>
+    to zero when the homing procedure is either completed or aborted.
+    Note that modern controllers, depending on their firmware and configuration,
+    may do different things. Examples are home into the limit switch, move
+    into a limit switch, return and search for a home switch or other sequences.
+    Often HOMF and HOMR then yield the same functionality. 
+    And the controller may choose to do nothing, if a motor is not homable.
+</td>
   </tr>
   <tr valign="top">
     <td><br>
@@ -2875,11 +2881,18 @@ <h2>Servo fields</h2>
     <td>R/W</td>
     <td>Enable control</td>
     <td>RECCHOICE</td>
-    <td>(0:"Disable", 1:"Enable")&nbsp; Enable/Disable closed-loop position control.&nbsp; 
-    This field is active only if the GAIN_SUPPORT bit in the MSTA is true.&nbsp; 
-    This field is set by both the user and device support.&nbsp; CNEN is set to <i>Disable</i> 
-    by device support when it detects a motion controller error; e.g. maximum 
-    following error exceeded.</td>
+    <td>This field is active only if the GAIN_SUPPORT bit in the MSTA is true.
+     The function of this field is depending on the motion controller.
+     This field is set by both the user and device support.
+    <li>
+     Some (older?) controllers can switch between open- and closed-loop. (0: open loop, 1: closed loop)
+    </li>
+    <li>
+     Some controllers use this field to enable torque control
+    </li>
+    <li>
+     Most modern controllers  use this field to enable/disable the motor (amplifier/driver)
+    </li>
   </tr>
   <tr valign="top">
     <td>PCOF</td>