Delta Tau GEO BRICK LV Manuel D’Utilisation

 

 

For PMAC2-style Servo ICs, the M-variable definitions for the position-capture registers are shown in the 
following table: 

0 X:$078003,0,24,S 

X:$07800B,0,24,S 

X:$078013,0,24,S 

X:$07801B,0,24,S 

1 X:$078103,0,24,S 

X:$07810B,0,24,S 

X:$078113,0,24,S 

X:$07811B,0,24,S 

2 X:$078203,0,24,S 

X:$07820B,0,24,S 

X:$078213,0,24,S 

X:$07821B,0,24,S 

3 X:$078303,0,24,S 

X:$07830B,0,24,S 

X:$078313,0,24,S 

X:$07831B,0,24,S 

4 X:$079003,0,24,S 

X:$07900B,0,24,S 

X:$079013,0,24,S 

X:$07901B,0,24,S 

5 X:$079103,0,24,S 

X:$07910B,0,24,S 

X:$079113,0,24,S 

X:$07911B,0,24,S 

6 X:$07A203,0,24,S 

X:$07A20B,0,24,S 

X:$07A213,0,24,S 

X:$07A21B,0,24,S 

7 X:$07A303,0,24,S 

X:$07A30B,0,24,S 

X:$07A313,0,24,S 

X:$07A31B,0,24,S 

8 X:$07B203,0,24,S 

X:$07B20B,0,24,S 

X:$07B213,0,24,S X:$07B21B,0,24,S 

9 X:$07B303,0,24,S 

X:$07B30B,0,24,S 

X:$07B313,0,24,S X:$07B31B,0,24,S 

The value in this register is referenced to the power-up/reset position of the sensor.  That is, the counter is 
set to zero at power-up/reset, and it counts from there.  It does not get reset to zero if the motor using it 
for feedback is homed.  If the travel of the sensor from the power-up/reset position goes more than +/-
8,388,608 (+/-2

23

) counts, the count value will roll over.  In this case, you must keep track of the rollover. 

Note that the act of reading the position-capture register resets the trigger logic, automatically re-arming it 
for another trigger.  It is a good idea to perform a dummy read of the capture register before starting a 
capture sequence to make sure the trigger logic is armed (the standard move-until-trigger functions do this 
automatically).  If you are also reading the fractional-count capture register (see below), read that register 
first to ensure that both it and the whole-count register represent the same triggered position. 

Fractional-Count Position-Capture Register 
In PMAC(2)-style Servo ICs of Revision D and newer (started shipments in 2002), it is possible to 
capture timer-estimated sub-count position as well as the whole-count position described above.  This is 
most commonly used with the Acc-51 high-resolution sinusoidal-encoder interpolator, but can be used 
with quadrature encoders as well. 

If variable I7mn9 for Channel n of Servo IC m is set to 1, this function is enabled.  (Note that if this is 
enabled, the traditional “software 1/T” interpolation registers are disabled.)  In this case, bits 12 – 23 of 
the Y-register of the channel’s base address (Y:$078000 for Servo IC 0 Channel 1), contain the captured 
fractional count value.  Bit 23 has a value of ½-count, bit 22 has a value of ¼-count, and so on.  A count 
in this context is a “hardware count,” which is not necessarily the same as the motor’s “software count.” 

The M-variable definitions for the fractional-count position-capture registers are shown in the following 
table.  The suggested M-variable for Motor xx, assuming the standard matching of channels to motors, is 
Mxx83. 

0 Y:$078000,12,12,U 

Y:$078008,12,12,U 

Y:$078010,12,12,U 

Y:$078018,12,12,U 

1 Y:$078100,12,12,U 

Y:$078108,12,12,U 

Y:$078110,12,12,U 

Y:$078118,12,12,U 

2 Y:$078200,12,12,U 

Y:$078208,12,12,U 

Y:$078210,12,12,U 

Y:$078218,12,12,U 

3 Y:$078300,12,12,U 

Y:$078308,12,12,U 

Y:$078310,12,12,U 

Y:$078318,12,12,U 

4 Y:$079000,12,12,U 

Y:$079008,12,12,U 

Y:$079010,12,12,U 

Y:$079018,12,12,U 

5 Y:$079100,12,12,U 

Y:$079108,12,12,U 

Y:$079110,12,12,U 

Y:$079118,12,12,U 

6 Y:$07A200,12,12,U 

Y:$07A208,12,12,U 

Y:$07A210,12,12,U 

Y:$07A218,12,12,U 

7 Y:$07A300,12,12,U 

Y:$07A308,12,12,U 

Y:$07A310,12,12,U 

Y:$07A318,12,12,U 

8 Y:$07B200,12,12,U 

Y:$07B208,12,12,U 

Y:$07B210,12,12,U Y:$07B218,12,12,U 

9 Y:$07B300,12,12,U 

Y:$07B308,12,12,U 

Y:$07B310,12,12,U Y:$07B318,12,12,U