Delta Tau GEO BRICK LV User Manual

 

$A 

2 

Triggered Time Base, 
running 

0 = PMAC IC 
1 = PMAC2 IC 

Time Base Scale Factor 

- 

$B 

2 

Triggered Time Base, 
armed 

0 = PMAC IC 
1 = PMAC2 IC 

Time Base Scale Factor 

- 

$C 

1 

Incremental Encoder, no 
or HW 1/T extension 

0 = No extension 
1 = Hardware 1/T 

- - 

$D 

3 

Exponential filter of 
parallel data 

None 

Max Change per Cycle 

Filter Gain (Inverse 

Time Constant) 

$E 

1 

Sum or difference of 
entries 

0 = no integration 
1 = integrate result 

- - 

$F 

- 

(Extended entry – type 
determined by 1

st

 digit of 

2

nd

 line) 

- - 

- 

$F/$0 3 

High-Resolution 
Interpolator 

0 = PMAC IC 
1 = PMAC2 IC 

$0 Method digit  & 

Address of 1

st

 A/D 

converter 

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 

Because most source addresses have a 7 in the second hex digit, the effect of setting the mode-switch bit 
to 1 is to change the second hex digit from 7 to F.  For example, an Acc-28 ADC entry that is $178005 
with the mode-switch bit at 0 is changed to $1F8005 with the mode-switch bit at 1. 

In the Software Reference Manual under the descriptions for I8000 – I8191, there is a detailed description 
for the setup of each type of entry, with extensive tables of the common source addresses for each.  The 
PMAC Executive program’s setup menu for the conversion table has good pick lists of source addresses 
for each method. 

Entry Subsequent Setup I-Variables 

If the method defined in the first line specifies an entry of more than one line, the next one or two setup 
lines (I-variables) in the table are further setup values for this entry.  The meaning of these subsequent 
lines is dependent on the method; the above table gives a brief description of what these are, and the 
Software Reference Manual describes these in detail. 

Next Entry 

After the last line of any entry, whether the entry is one, two or three lines long, the next line in the table 
is the first line of the next entry.  For example, if the first line in the table is a three-line entry, I8000, 
I8001, and I8002 will be used to set up that entry, and I8003 will be the first setup line of the next entry. 

End of Table 

If a setup line (I-variable) that could be the first line of an entry is set to 0, this marks the end of the active 
table.  Even if there are valid entries below this point in the table, they will not be executed. 

The column of the encoder conversion table that is in X-memory contains the processed results of the 
table.  The 24-bit data in this column for the last line of the entry (the only line for a single-line entry) is 
the final processed result.  This value will be used for subsequent operations in the Turbo PMAC.  The 
data in this column for previous lines (if any) of the entry contain intermediate results; these generally are 
for internal use only.