docs/motorRecord.html: CNEN is implementation specific

The CNEN field has been developed with motion controllers which can
switch between open- and closed-loop.
In modern controllers this is hard-coded inside the motion controller,
or to be more exact, sometimes the configuration of ths controller.
In other words, the CNEN field has been used to enable or disable the
motor.
Make this different usage and functionality more clear.

docs/motorRecord.html

@@ -2875,11 +2875,18 @@ <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>