Reference Manual

16-Axis MACRO CPU Software Reference Manual
16-Axis MACRO Station MI-Variable Reference 19
When this data is passed to a PMAC, and it reads this data for servo use with Ix03, Ix04, Ix05, or Ix93, it
expects to find data in units of 1/32 of a count. Therefore, PMAC software regards this format as
producing 128 counts per line. (The fact that the hardware counter used produces 4 counts per line is not
relevant to the actual use of this format; this fact would only be used when reading the actual hardware
counter for debugging purposes.)
Example:
This format is used to interpolate a linear scale with a 40-micron pitch (40µm/line), producing a
resolution of about 10 nanometers (40,000/4096), used as position feedback for a motor. PMAC
considers a count to be 1/128 of a line, yielding a count length of 40/128 = 0.3125 µm. To set user units
of millimeters for the axis, the axis scale factor would be:
UserUnit
counts
3200
m3125.0
count
*
mm
m1000
*
UserUnit
mm1
actorAxisScaleF ==
µ
µ
ACC-28 Style A/D Entries ($1x, $5x): The A/D feedback entries read from the high 16-bits of the
specified address and shift the data right three bits so that the least significant bit of the processed result in
bit 5. Unlike the parallel feedback methods, this method will not roll over and extend the result.
This data typically comes from an ACC-28E backplane A/D board.
The $1x method processes the information directly, essentially a copying with shift. The $5x integrates
the input value as it copies and shifts it. That is, it reads the input value, shifts it right three bits, adds the
bias term in the second line, and adds this value to the previous processed result.
If the second digit ‘x’ of the entry is ‘0’, the 16-bit source value is treated as a signed quantity; if it is ‘8’,
the 16-bit value is treated as an unsigned quantity. Presently, the only A/D accessory of this format that
can interface to the 16-axis MACRO Station is the ACC-28E, which provides an unsigned value, so $18
and $58 should be used.
The following table shows the entries for ACC-28E backplane converter board ADCs. The ‘m’
represents the conversion method, either ‘1’ or ‘5’.
Entries for ACC-28E ADCs
ACC-28E
Base Address
Entry for ADC1 Entry for ADC2 Entry for ADC3 Entry for ADC4
$8800 $m88800 $m88801 $m88802 $m88803
$9800 $m89800 $m89801 $m89802 $m89803
$A800 $m8A800 $m8A801 $m8A802 $m8A803
$B800 $m8B800 $m8B801 $m8B802 $m8B803
$8840 $m88840 $m88841 $m88842 $m88843
$9840 $m89840 $m89841 $m89842 $m89843
$A840 $m8A840 $m8A841 $m8A842 $m8A843
$B840 $m8B840 $m8B841 $m8B842 $m8B843
$8880 $m88880 $m88881 $m88882 $m88883
$9880 $m89880 $m89881 $m89882 $m89883
$A880 $m8A880 $m8A881 $m8A882 $m8A883
$B880 $m8B880 $m8B881 $m8B882 $m8B883
$88C0 $m888C0 $m888C1 $m888C2 $m888C3
$98C0 $m898C0 $m898C1 $m898C2 $m898C3
$A8C0 $m8A8C0 $m8A8C1 $m8A8C2 $m8A8C3
$B8C0 $m8B8C0 $m8B8C1 $m8B8C2 $m8B8C3