TMC 188/40 Motion Control Module
Motion Control Parameters
Delta Computer Systems, Inc. 360/254-8688
37
ACCELERATION
(Default: 1000)
This field determines the acceleration of the axis. The field works in two ways depending on the
setting of bits 15 and 16 in the MODE word. If the bits are clear (Acceleration/Deceleration Mode 0),
the value in these fields is a distance expressed in position units. If the SCALE is set so one position
unit equaled 0.001 inch, then a value of 5000 represents a ramp of 5.000 inches.
If bit 15 is clear and bit 16 is set (A/D Mode 1), this field is an acceleration or deceleration rate and is
expressed in 1000 position units/sec/sec. If the SCALE is set so one position unit equals 0.001 inch,
then a value of 200 represents an acceleration rate of 200 inches/sec/sec.
Ramping distance (expressed in position units) is simpler to use for applications where the SPEED
does not change. The relationship between the ramping distance, acceleration and speed is:
Speed
2
Ramp Distance =
Acceleration Rate x 2000
Speed
2
Acceleration Rate =
Ramp Distance x 2000
See pages 33 to 36 for more information about the MODE word.
DECELERATION
(Default: 1000)
This field is similar to the ACCELERATION field except it specifies the deceleration ramp or
deceleration rate.
SPEED
(Default: 1000)
The SPEED parameter sets the constant speed to be achieved after acceleration. The SPEED is
expressed in position units/second. If the SCALE is set so one position unit equals 0.001 inch, a
speed of 25 inches per second is expressed as 25000.
NOTE:
Changing the SPEED without changing the ACCELERATION and DECELERATION distances
(expressed in position units) will change the acceleration and deceleration rates. See the control
equations on page 72. If you set the SPEED to zero, the axis will do the same as a halt. Use the
HALT command rather than set the SPEED to zero.
REQUESTED POSITION
The REQUESTED POSITION is the position the axis is to move to. This value is bounds-checked by
the TMC 188/40 using the EXTEND LIMIT and RETRACT LIMIT and is then used as the COMMAND
POSITION value. It is also used as a parameter for other commands (E, O, and C).
