Reference Manual

PMAC 2 Software Reference

PMAC I-Variable Specification 59

I103=$10722 I125=$C000

This would permit homing on interferometer data with HMFL1 triggering.

Note:

In the extended version, it is obviously easier to specify this

parameter in hexadecimal form. With I9 at 2 or 3, the value of this

variable will be reported back to the host in hexadecimal form.

Capture on following error: If bit 17 of Ix03 is set to 1, then the trigger for position capture

of this motor is a true state on the warning following error status bit for the motor. If bit

17 is at the default of 0, the trigger for position capture is the capture flag of the flag

registers as set by Ix25. The trigger is used in two types of moves: homing search moves

and programmed move-until-triggers. If bit 17 is set to 1, the triggered position must be

software captured, so bit 16 must also be set to 1 to specify software captured bit position.

Hardware Capture with Normal-Resolution Feedback

: If bit 18 of Ix03 is set to its default

value of 0 when hardware position capture is used in a triggered move such as a homing-

search move, the captured data (whether whole-count only or including sub-count data) is

processed to match servo feedback of “normal” resolution (5 bits of fractional count data

per hardware whole count). This setting is appropriate for digital quadrature feedback or

for “low-resolution” interpolation of a sinusoidal encoder.

Hardware Capture with High-Resolution Interpolated Feedback

: If bit 18 (value $40000, or

262,144) is set to 1 when hardware position capture is used in a triggered move, the

captured data (whether whole-count only or including sub-count data) is processed to

match servo feedback of “high” resolution (10 bits of fractional count data per hardware

whole count). This setting is appropriate for “high-resolution” interpolation of a sinusoidal

encoder through an ACC-51x interpolator.

Whole-Count Capture

: If bit 19 of Ix03 is set to 0 when hardware position capture is used

in a triggered move such as a homing-search move, only the whole-count captured position

controllers, and on PMAC2 controllers with Servo ICs older than Revision “D” (Revision

“D” ICs started shipping in early 2002).

Sub-Count Capture

: If bit 19 (value $80000, or 524,288) is set to 1 when hardware

position capture is used in a triggered move, both the whole-count captured position

position. This setting can only be used on PMAC2 controllers with Servo ICs of Revision

“D” or newer. I9n9 for the Channel “n” used for the capture must be set to 1 to enable the

hardware sub-count estimation. This setting is typically used for registration or probing

triggered moves with interpolated sinusoidal encoder feedback. (Even with interpolated

sinusoidal encoder feedback, homing-search moves will probably be done without sub-

count captured data, to force a home position referenced to one of the four “zero-crossing”

positions of the sine/cosine signals.)