Changeset 951 for softGlue_examples

Timestamp:

Jun 20, 2012 12:50:50 PM (11 years ago)

Author:

mooney

Message:

Added div-by-N

File:

• softGlue_examples/source/motor_accel_gate/index.rst (modified) (3 diffs)

softGlue_examples/source/motor_accel_gate/index.rst

@@ -16 +16 @@
 
 One common way to implement a fly scan is to trigger a detector with motor
-pulses.  You might want the detector to acquire on every M\ :sup:`th` pulse, for example,
-and this circuit assumes the detector can be configured to do that, if needed. 
-(If it cannot, the circuit could easily be modified to do the division by M.) 
-But you might want motor pulses from the acceleration and deceleration portions
-of a move to be ignored, and to acquire only while the motor is moving at
-constant speed.  This circuit handles that part of the problem.
+pulses.  You might want the detector to acquire on every :math:`N^{th}` pulse,
+for example, but to refrain from acquiring during the acceleration and
+deceleration portions of a move.  That's what this circuit does.
 
 If you know the number of steps a stepper motor will move during its
@@ -31 +28 @@
 .. math:: N_a = ((VBAS + VELO)/2) \times (ACCL / MRES)
 
-where, ``VBAS``, ``VELO``, ``ACCL``, and ``MRES`` are motorRecord fields.
+where, :math:`VBAS`, :math:`VELO`, :math:`ACCL`, and :math:`MRES` are
+motorRecord fields.
 
-The number of constant-speed steps, N\ :sub:`c`, is then
+The number of constant-speed steps, :math:`N_c`, is then
 
 .. math:: N_c = ((VAL_{end}-VAL_{start})/MRES) - 2N_a
 
-where ``VAL``\ :sub:`end` and ``VAL``\ :sub:`start` are the final and initial
+where :math:`VAL_{end}` and :math:`VAL_{start}` are the final and initial
 values of the motorRecord ``VAL`` field.
 
@@ -47 +45 @@
         :width: 100%
 
-This circuit accepts negative-going motor pulses at input signal 1,
-gates out the first 11 (the value of ``DnCntr-1_PRESET``), and from then on
-sends motor pulses to output pin 17 until a total of 31 (the value of
-``DnCntr-2_PRESET``) have been sent. Thus, the detector would see only the 20
-pulses that occurred while the motor was moving at constant speed.  The circuit
-is reset by writing ``1!`` (positive-going pulse) to the input of ``BUF-1``.
+This circuit accepts negative-going motor pulses at input signal 1, inverts
+them, gates out the first :math:`N_a` (the value of ``DnCntr-1_PRESET``), and
+from then on sends pulses to a divide-by-N circuit, until a total of
+:math:`N_a+N_c` (the value of ``DnCntr-2_PRESET``) have been sent. The
+divide-by-N sends every :math:`N^{th}` rising edge to output pin 17.  Thus, the
+detector would see only the :math:`(N_a+N_c)/N` divided pulses that occurred
+while the motor was moving at constant speed.  The circuit is reset by writing
+``1!`` (positive-going pulse) to the input of ``BUF-1``.
 
 Down counter ``DnCntr-1``, and flipflop ``DFF-1``, together produce a gate