Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 233
$A
2
Triggered Time Base,
running
0 = PMAC(1) IC
1 = PMAC2 IC
Time Base Scale
Factor
-
$B
2
Triggered Time Base,
armed
0 = PMAC(1) IC
1 = PMAC2 IC
Time Base Scale
Factor
-
$C
1
Incremental Encoder, no
or HW 1/T extension
0 = No Extension
1= HW 1/T Ext
-
-
$D
3/5
Low-pass filter of parallel
data
0 = Exponential
filter
1 = Tracking
Filter
Max Change per
Cycle
Filter Gain
(Inverse Time
Constant);
(5) Integral Gain
$E
1
Sum or difference of
entries
None
-
-
$F
-
(Extended entry – type
determined by 1
st
digit of
2
nd
line)
-
-
-
$F/$0
3
High-Resolution
Interpolator Feedback
0 = PMAC(1) IC
1 = PMAC2 IC
$0 Method digit
& Address of 1
st
A/D converter
A/D Bias Term
$F/$1
5
High-Resolution
Interpolator Diagnostic
-
-
Active A/D Bias
Term
$F/$2
2
Byte-wide parallel Y-
word data, no filtering
0 = normal shift
1 = unshifted
$2 and
Width/Offset
Word
-
$F/$3
3
Byte-wide parallel Y-
word data, with filtering
0 = normal shift
1 = unshifted
$3 and
Width/Offset
Word
Max Change per
Cycle
$F$4
3
Resolver Conversion
0 = CW
1 = CCW
A/D Bias Term
Incremental Encoder Entries ($0, $8, $C): These three conversion table methods utilize the
incremental encoder registers in the Servo ICs. Each method provides a processed result with the units of
(1/32) count – the low five bits of the result are fractional data.
Software 1/T Extension: With the $0 method, the fractional data is computed by dividing the Time Since
Last Count register by the Time Between Last 2 Counts register. This technique is known as 1/T
extension and is the default and most commonly used method. It can be used with a digital incremental
encoder connected directly to the Turbo PMAC, through either PMAC-style or PMAC2-style Servo ICs.
Note:
1/T extension with eight bits of fractional resolution (units of 1/256 count) can be
gotten using the intermediate result value of the triggered time-base conversion in
running mode. This intermediate result is in the first line of the entry. If used for
position data, one true count of the position is considered by Turbo PMAC
software to be eight counts.
Parallel Extension: With the $8 method, the fractional data is computed by reading the five inputs at bits
19-23 either of the specified address (USERn, Wn, Vn, Un, and Tn flag inputs, respectively) if the mode