MPC-385 SERIES OPERATION MANUAL – REV. 3.21K (20201120)
Position values in microns (micrometers or µm) should be data typed as double-precision
floating point variables (“double” in C/C++ and MATLAB, “DBL” in LabVIEW, etc.).
Note that in Python, incorporating the optional NumPy package brings robust data typing
like that used in C/C++ to your program, simplifying coding and adding positioning
accuracy to the application.
9. Position Value Bit Ordering: All 32-bit position values transmitted to, and received from,
the controller must be bit/byte-ordered in “Little Endian” format. This means that the
least significant bit/byte is last (last to send and last to receive). Byte-order reversal may
be required on some platforms. Microsoft Windows, Intel-based Apple Macintosh systems
running Mac OS X, and most Intel/AMD processor-based Linux distributions handle byte
storage in Little-Endian byte order so byte reordering is not necessary before converting
to/from 32-bit “long” values. LabVIEW always handles “byte strings” in “Big Endian”
byte order irrespective of operating system and CPU, requiring that the four bytes
containing a microsteps value be reverse ordered before/after conversion to/from a
multibyte type value (I32, U32, etc.). MATLAB automatically adjusts the endianess of
multibyte storage entities to that of the system on which it is running, so explicit byte
reordering is generally unnecessary unless the underlying platform is Big Endian. If your
development platform does not have built-in Little/Big Endian conversion functions, bit
reordering can be accomplished by first swapping positions of the two bytes in each 16-bit
half of the 32-bit value, and then swap positions of the two halves. This method efficiently
and quickly changes the bit ordering of any multibyte value between the two Endian
formats (if Big Endian, it becomes Little Endian, and if Little Endian, it becomes then Big
Endian).
10. Travel Lengths and Durations: “Move” commands might have short to long distances of
travel. If not polling for return data, an appropriate delay should be inserted between the
sending of the command sequence and reception of return data so that the next command
is sent only after the move is complete. This delay can be auto calculated by determining
the distance of travel (difference between current and target positions) and rate of travel.
This delay is not needed if polling for return data. In either case, however, an appropriate
timeout must be set for the reception of data so that the I/O does not time out before the
move is made and/or the delay expires.
11. Orthogonal Move Speed: Full speed for the “Orthogonal Move ‘M’” command is 5000
microns/sec. (5 mm/sec. or microns/millisecond) for single-axis movements (3000 µm/sec.
(3 mm/sec. or µm/ms) for MP-225/M).
12. Straight-Line Move Speeds: Actual speed for the “Straight-Line Move ‘S’“ command can
be determined with the following formula: (1300 / 16) * (sp +1), where 1300 is the
maximum speed in microns/second and “sp” is the speed level 0 (slowest) through 15
(fastest). For mm/second or microns/millisecond, multiply result by 0.001.
Table 5-21. Straight-line move ‘S’ command speeds.
To Next Page
Loading...
