Delta Tau GEO MACRO DRIVE User Manual download pdf (Page 144)

Geo MACRO Drive User Manual

132 Turbo PMAC2 Related I-Variable Reference

feedback for Motor xx, as specified by Ixx03, and the conversion table, must be received through the

encoder counter of the same hardware interface channel as used for the flag set (e.g. if flag set 2 is used,

encoder 2 must be used for position-loop feedback). The advantage of the hardware position capture is

that it is immediate, and accurate to the exact count at any speed.

Software Capture: If Ixx97 is set to 1 or 3 (bit 0 = 1), Turbo PMAC will use a software-captured

position for the trigger position. In this case, Turbo PMAC uses the register whose address is specified

by Ixx03, usually a register in the encoder conversion table, for the trigger position. The advantage of

software capture is that it can be used with any type of feedback, or when the position encoder channel is

not the same as the flag channel. The disadvantage is that the software capture can have up to 1

background cycle delay (typically 2-3 msec), which limits the accuracy of the capture.

Input Trigger: If Ixx97 is set to 0 or 1, (bit 1 = 0), Turbo PMAC will use the input capture trigger flag in

the Servo IC flag register addressed by Ixx25 as the trigger for the move. This input trigger is created by

an edge of the index input and a flag input for the channel as specified by I6mn2 and I6mn3 for the

selected Channel n of Servo IC m, or if a MACRO flag register is selected by Ixx25, with bit 18 of Ixx25

set to 1, the input trigger condition is set by MI-variables on the MACRO station.

Error Trigger: If Ixx97 is set to 2 or 3, (bit 1 = 1), Turbo PMAC will use the “warning following error”

status bit in the motor status word as the trigger for the move. When this bit changes from 0 to 1 because

the magnitude of the following error for the motor has exceeded the warning limit in Ixx11, Turbo PMAC

will consider this the trigger condition for the triggered move. Because there is nothing in this mode that

can create a hardware capture, only software capture should be used with error trigger (Ixx97 = 3).

Summarizing the values of Ixx97, and their effect:

• Ixx97 = 0: Input trigger, hardware position capture

• Ixx97 = 1: Input trigger, software position capture

• Ixx97 = 2: Error trigger, hardware position capture (not useful!)

• Ixx97 = 3: Error trigger, software position capture

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Delta Tau GEO MACRO DRIVE User Manual Page 144