Chapter4 FunctionalOverview
7344/7334Hardware User Manual 4-2 ni.com
The DSP chip isa separate processor that operates independently from
the CPUbut is closely synchronized by an internal packet-based command,
data, and messaging eventstructure. The 7344/7334 contro llersare true
multiprocessing and multitasking embedded controllers.
The advancedarchitecture of the 7344/7334 co ntroller enables advanced
motionfeatures, such as enhanced PID functions. Refer to the FlexMotion
SoftwareReference Manual for more information on the features available
on the 7344/7334 controllers.
TrajectoryGenerators
The7344/7334 controller trajectory generators calculate the instantaneous
position command that controls acceleration and velocity while it moves
the axis to its target position. This command is then sent to the PID servo
loop or stepper pulse generator, depending on how you configure the axis.
Toimplement infinite trajectory control, the 7344/7334 controller has
eighttrajectory generators implemented in the DSP chip—two per axis.
Eachgenerator calculates an instantaneous position each PID update
period. While simple point-to-point moves require only one trajectory
generator,two simultaneous generators are required for blended m oves
and infinitetrajectory co ntrolprocessi ng.
Analog Feedback
The7344 /7334 controller has an 8-channel multiplexed, 12-bit ADC. The
converted analog values are broadcast to both the DSP and CPU via a
dedicated internalhigh-speed serial bus. The multiplexer scan rate is
approximately 50 µs per enabled ADC channel. This provides the high
sampling rates required for feedback loop closure, joystick inputs, or
monitoring analog sensors. Four of these channels are intended for
calibration, leaving the other four available for analog feedback.
Flash Memory
Nonvolatile memory on the 7344/7334 controller is implemented with
flashROM. This means that the 7344/7334 controller can electrically erase
andreprogram its own ROM. Since all the embedded firmware, including
theRTOS and DSP code,of the 7344 /7334 is stored in flash memory, you
canupgrade the onboard firmware contents in the field fo r support and new
feature enhancement.