Delta Tau GEO BRICK LV User Manual

 

 

1 I8000 

$3501 9 I8008 

$3509 

2 I8001 

$3502 10 I8009 

$350A 

3 I8002 

$3503 11 I8010 

$350B 

4 I8003 

$3504 12 I8011 

$350C 

5 I8004 

$3505 13 I8012 

$350D 

6 I8005 

$3506 14 I8013 

$350E 

7 I8006 

$3507 15 I8014 

$350F 

8  I8007 $3508  16  I8015 $3510 

For example, to use the result in the eighth line of the table for position-loop feedback for Motor 4, either 
of the following commands could be used: 

Even if the address is specified indirectly, it will still be reported back directly.  So in the above example, 
regardless of the way the value was specified, if Turbo PMAC is queried for the value of the I-variable, it 
will return the address – 

I403 
$3508 

Each conversion method is covered in detail in the description of the table’s I-variables in the Software 
Reference manual.  This section gives a brief overview. 

The most common conversion is for digital quadrature encoders (or other pulse trains, such as pulse and 
direction that feed these counters).  These are single-line entries.  The source addresses are always the 
base addresses of encoder channels in the Servo ICs.  A full list of these addresses is given in the 
Software Reference manual; a quick list of common addresses is given here: 

On-board PMAC-style channels 1 – 4: $78000, $78004, $78008, $7800C 
On-board PMAC2-style channels 1 – 4: $78000, $78008, $78010, $78018 
First four accessory PMAC2-style channels: $78200, $78208, $78210, $78218 

There are three conversion methods for this signal format: 

• 

Software 1/T Extension 

• 

Hardware 1/T Extension 

• 

No Extension 

Software 1/T Extension (Method digit $0) 

This is the most common method, and the one that is used in the table by default.  This method uses the 
quadrature counter for the integer count value, and computes the ratio of two timers to obtain the five bits 
of fractional count value.