Reference Manual

16-Axis MACRO CPU Software Reference Manual

18 16-Axis MACRO Station MI-Variable Reference

High Resolution: With the $Fx method, the table computes the fractional information using the A/D-

converter data from an ACC-51E high-resolution encoder interpolator, producing a value with 4096 states

per line. The entry must read both an encoder channel for the whole number of lines of the encoder, and a

pair of A/D converters to determine the location within the line, mathematically combining the values to

produce a single position value.

Encoder Channel Address: The first line of the three-line entry contains $F in the first hex digit and the

base address of the encoder channel to be read in the last four digits (bits 0 to 15). The following table

shows the possible entries for an ACC-51E in the station.

Entry First Lines for ACC-51E Backplane Interpolator Boards

ACC-51E # Channel 1 Channel 2 Channel 3 Channel 4

$F08000 $F08008 $F08010 $F08018

$F08040 $F08048 $F08050 $F08058

$F09000 $F09008 $F09010 $F09018

$F09040 $F09048 $F09050 $F09058

$F0A000 $F0A008 $F0A010 $F0A018

$F0A040 $F0A048 $F0A050 $F0A058

$F0B000 $F0B008 $F0B010 $F0B018

$F0B040 $F0B048 $F0B050 $F0B058

A/D Converter Address: The second line of the entry contains the base address of the first A/D

converter to be read in the last four digits (bits 0 to 15). The second A/D converter will be read at the

next higher address. The following table shows the possible settings when the ACC-51E is used.

Entry Second Lines for ACC-51E Backplane Interpolator Boards

ACC-51E # Channel 1 Channel 2 Channel 3 Channel 4

$008005 $00800D $008015 $00801D

$008045 $00804D $008055 $00805D

3rd $009005 $00900D $009015 $00901D

4th $009045 $00904D $009055 $00905D

5th $00A005 $00A00D $00A015 $00A01D

6th $00A045 $00A04D $00A055 $00A05D

7th $00B005 $00B00D $00B015 $00B01D

8th $00B045 $00B04D $00B055 $00B05D

A/D Bias Term: The third line of the entry contains the bias in the A/D converter values. This line

should contain the value that the A/D converters report when they should ideally report zero. The 16-

Axis MACRO Station subtracts this value from both A/D readings before calculating the arctangent.

Many users will leave this value at 0, but it is particularly useful to remove the offsets of single-ended

analog encoder signals.

This line is scaled so that the maximum A/D converter reading provides the full value of the 24-bit

). Generally, it is set by reading the A/D converter values directly as 24-bit values,

computing the average value over a cycle or cycles, and entering this value here.

Conversion Result: The result of the conversion is placed in the X-register of the third line of the entry.

Careful attention must be paid to the scaling of this 24-bit result. The least significant bit (Bit 0) of the

result represents 1/4096 of a line of the sine/cosine encoder.