Monitoring Variables Of Pr Mode - Delta ASDA-B3 Series User Manual

Motion Control

7.1.2 Monitoring variables of PR mode

The PR mode provides four monitoring variables for the servo commands and feedback status:
command position (PUU), PR command end register, feedback position (PUU), and position
7
error (PUU). These are described as follows:
Command position (PUU): monitoring variable code 001, simplified as Cmd_O (Command
1.
Operation). The target position of the motion command generated per scan cycle during
servo operation (updated every millisecond).
PR command end register: monitoring variable code 064, simplified as Cmd_E (Command
2.
End). The target position of the PR command. When a command is triggered, the servo
drive calculates the target position and then updates to PR command end register.
Feedback position (PUU): monitoring variable code 000, simplified as Fb_PUU (Feedback
3.
PUU). The feedback position of the motor.
Position error (PUU): monitoring variable code 002, simplified as Err_PUU (Error PUU).
4.
The difference between the command position (PUU) and the feedback position (PUU).
How these four monitoring variables work is shown in Figure 7.1.2.1. After the servo issues a
Position command, the servo sets the position of Cmd_E once the target position data is
acquired. The motor operates to the target position based on the PR path setting. Cmd_O
calculates the amount of command difference in each fixed cycle and sends it to the servo drive,
where it is treated as a dynamic command. Fb_PUU is motor encoder feedback position and
Err_PUU is the difference of subtracting Fb_PUU from Cmd_O.
7-6
Err_PUU
Before
Fb_PUU
command
Cmd_O
issued
Cmd_E
Err_PUU
After
command Fb_PUU
issued
Cmd_O
Command in
execution
Command
completed
Motor
positioned
Figure 7.1.2.1 Timing diagram for PR mode monitoring variables
Err_PUU
Fb_PUU
Cmd_O
Err_PUU
Cmd_E
Cmd_E
Fb_PUU
Cmd_O
Cmd_E
Err_PUU
Fb_PUU
Cmd_O
Cmd_E
ASDA-B3