Delta MMC120 User Manual
Page 31
MMC120 Linear Motion Control Module
Motion Control Parameters
Delta Computer Systems, Inc. 360/254-8688
31
9.0110(
µ
s/in) x 120 (MHz)
Example 2
For a system using a magnetostrictive transducer with a calibration number of 9.0110
µ
s per inch and
a position unit of 0.1 millimeter, the SCALE will be:
254(Position Units Per Inch) X 32768
SCALE =
= 7697
9.0110(
µ
s/in) x 120 (MHz)
OFFSET (Default: 0)
OFFSET is used to shift the ACTUAL POSITION with respect to the transducer zero. The OFFSET is
specified in Position Units and is equal to the desired ACTUAL POSITION at zero TRANSDUCER
COUNTS. It is defined as:
(P0 - P1)
OFFSET = P0 -
x C0
(C0 - C1)
The P0 and P1 commands can help calculate the OFFSET parameter. See page 82 for additional information.
CAUTION: When using OFFSET, you must be familiar with the limitations of 16 bit math.
EXTEND LIMIT (Defaults to current position on power-up)
The EXTEND LIMIT specifies the maximum requested position value that the MMC120 will allow as a
COMMAND VALUE. (When the SCALE is negative, this is the minimum value.) A COMMAND VALUE
that exceed this value will be set to the EXTEND LIMIT, and the PARAMETER ERROR bit (bit 5) in the
STATUS word will be set. The EXTEND LIMIT is given in Position Units. On startup the EXTEND LIMIT
defaults to the current position of the axis. New EXTEND and RETRACT LIMITS must be issued with a 'P'
command before the axis will move.
NOTE: The EXTEND LIMIT must be changed when the SCALE or OFFSET parameters are changed. Extending
is the direction that gives increasing TRANSDUCER COUNTS.
RETRACT LIMIT (Defaults to current position on power-up)
The RETRACT LIMIT specifies the minimum value the MMC120 will allow as a position COMMAND
VALUE. (When the SCALE is negative, this is the maximum value.) A COMMAND VALUE below this
value will be set to the RETRACT LIMIT. The RETRACT LIMIT is given in Position Units. On startup the
RETRACT LIMIT defaults to the current position of the axis. New EXTEND and RETRACT LIMITS must
be entered, then a 'P' command sent, before the axis will move.
NOTE: The RETRACT LIMIT must be changed when the SCALE or OFFSET parameters are changed.
PROPORTIONAL GAIN (Default: 1) Range: 0 to 65535
The PROPORTIONAL GAIN specifies the amount of drive added to the output for each unit of position error.
It is defined as: