Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
222
Executing Individual Motor Moves
Triggered Motor Moves
Triggered moves in Turbo PMAC are double moves, with a pre-trigger portion and a post-trigger portion.
Upon the trigger event, Turbo PMAC will break into the pre-trigger move and calculate a post-trigger
move ending at a pre-specified distance from the trigger point.
Upon the trigger event, Turbo PMAC will break into the pre-trigger move and calculate a post-trigger
move ending at a pre-specified distance from the trigger point.
Types of Triggered Moves
There are three types of triggered motor moves:
1. Homing search moves (on-line or motion-program)
2. On-line jog-until-trigger moves
3. Motion-program RAPID move-until trigger
2. On-line jog-until-trigger moves
3. Motion-program RAPID move-until trigger
These moves all work basically in the same manner, just in different contexts. Triggering and position-
capture functions are the same in all three types of moves. Each will be described in detail below.
capture functions are the same in all three types of moves. Each will be described in detail below.
Types of Trigger Conditions
There are fundamentally two types of triggers for these triggered moves: input triggers and following-
error triggers. Bit 1 of motor variable Ixx97 determines which of these is used for the motor’s triggered
moves.
error triggers. Bit 1 of motor variable Ixx97 determines which of these is used for the motor’s triggered
moves.
Input Triggering
If bit 1 of Ixx97 is 0 (Ixx97 = 0 or 1), the trigger condition for the motor is an input trigger. In this, the
default case, the trigger is caused by one or two of the inputs mapped into the register whose address is
specified by Ixx25. Usually, Ixx25 contains the address of a flag register in a Servo IC, or a register in
memory containing the contents of flag data copied in from the MACRO ring. For the super-accurate
hardware-capture (see below), Ixx25 must specify the flags of the same hardware channel as the encoder
used for position-loop feedback. If bit 18 of Ixx24 is set to 1, Turbo PMAC expects the capture trigger
and position to come from over the MACRO ring; if bit 18 of Ixx24 is 0, Turbo PMAC expects these
from hardware channels directly connected to the controller’s CPU.
default case, the trigger is caused by one or two of the inputs mapped into the register whose address is
specified by Ixx25. Usually, Ixx25 contains the address of a flag register in a Servo IC, or a register in
memory containing the contents of flag data copied in from the MACRO ring. For the super-accurate
hardware-capture (see below), Ixx25 must specify the flags of the same hardware channel as the encoder
used for position-loop feedback. If bit 18 of Ixx24 is set to 1, Turbo PMAC expects the capture trigger
and position to come from over the MACRO ring; if bit 18 of Ixx24 is 0, Turbo PMAC expects these
from hardware channels directly connected to the controller’s CPU.
Trigger Signal(s) and Edge(s)
Two setup variables for the Servo IC channel determine which edges of which signals will cause the
trigger. I7mn2 for Servo IC m Channel n (node-specific variable MI912 on a MACRO Station) specifies
whether the index channel is used or not, whether an input flag is used or not, and which edges of the
index and/or flag will be cause the trigger. If both index and flag are selected, the two signals are
combined with Boolean hardware logic inside the IC to create the trigger.
Two setup variables for the Servo IC channel determine which edges of which signals will cause the
trigger. I7mn2 for Servo IC m Channel n (node-specific variable MI912 on a MACRO Station) specifies
whether the index channel is used or not, whether an input flag is used or not, and which edges of the
index and/or flag will be cause the trigger. If both index and flag are selected, the two signals are
combined with Boolean hardware logic inside the IC to create the trigger.
If I7mn2 specifies the use of a flag, I7mn3 (node-specific variable MI913 on a MACRO Station) selects
which of the four input flags for the channel is used. For a PMAC-style Servo IC, the choices are HMFL,
+LIM, -LIM, and FAULT; for a PMAC2-style Servo IC, the choices are HOME, MLIM, PLIM, and
USER.
which of the four input flags for the channel is used. For a PMAC-style Servo IC, the choices are HMFL,
+LIM, -LIM, and FAULT; for a PMAC2-style Servo IC, the choices are HOME, MLIM, PLIM, and
USER.
Edge vs. Level Triggering
There is a subtle difference between PMAC-style and PMAC2-style Servo ICs that lead to different
modes of failure if the trigger move starts with the inputs already in the trigger state (there is no
difference otherwise). PMAC-style Servo ICs are edge triggered, requiring a transition (edge) from non-
trigger state to trigger state to generate the actual trigger. With these ICs, there will be no trigger
generated in this case, and the pre-trigger move will continue, perhaps indefinitely.
There is a subtle difference between PMAC-style and PMAC2-style Servo ICs that lead to different
modes of failure if the trigger move starts with the inputs already in the trigger state (there is no
difference otherwise). PMAC-style Servo ICs are edge triggered, requiring a transition (edge) from non-
trigger state to trigger state to generate the actual trigger. With these ICs, there will be no trigger
generated in this case, and the pre-trigger move will continue, perhaps indefinitely.
However, PMAC2-style Servo ICs are level triggered only requiring that the IC see the input(s) in the
trigger state to generate the actual trigger. With these ICs, a trigger will be generated immediately in this
case, and there will be little or no motion at all.
trigger state to generate the actual trigger. With these ICs, a trigger will be generated immediately in this
case, and there will be little or no motion at all.