LM629N-8/NOPB National Semiconductor, LM629N-8/NOPB Datasheet - Page 9

• Manufacturer Part Number: LM629N-8/NOPB
• Description: IC CONTROLLER PREC MOTION 28-DIP
• Manufacturer: National Semiconductor

Specifications of LM629N-8/NOPB

• Applications: DC Motor Controller, Servo
• Number Of Outputs: 1
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 28-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Other names: *LM629N-8; *LM629N-8/NOPB; LM629N-8

Theory of Operation
Control Algorithm
Sample Intervals
VELOCITY PROFILE (TRAJECTORY) GENERATION
The trapezoidal velocity profile generator computes the de-
sired position of the motor versus time. In the position mode
of operation, the host processor specifies acceleration, maxi-
mum velocity, and final position. The LM628 uses this infor-
mation to affect the move by accelerating as specified until
the maximum velocity is reached or until deceleration must
begin to stop at the specified final position. The deceleration
rate is equal to the acceleration rate. At any time during the
move the maximum velocity and/or the target position may
be changed, and the motor will accelerate or decelerate
accordingly. Figure 10 illustrates two typical trapezoidal ve-
Proportional Integral Derivative (PID) (plus programmable integration limit)
Derivative Term: Programmable from 2048/f
65,536 µs for an 8.0 MHz clock).
Proportional and Integral: 2048/f
TABLE 1. System Specifications Summary (Continued)
(Continued)
FIGURE 9. Quadrature Encoder Signals
FIGURE 10. Typical Velocity Profiles
CLK
9
locity profiles. Figure 10(a) shows a simple trapezoid, while
Figure 10(b) is an example of what the trajectory looks like
when velocity and position are changed at different times
during the move.
When operating in the velocity mode, the motor accelerates
to the specified velocity at the specified acceleration rate and
maintains the specified velocity until commanded to stop.
The velocity is maintained by advancing the desired position
at a constant rate. If there are disturbances to the motion
during velocity mode operation, the long-time average veloc-
ity remains constant. If the motor is unable to maintain the
specified velocity (which could be caused by a locked rotor,
CLK
to (2048
*
00921911
256)/f
CLK
00921912
in steps of 2048/f
CLK
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(256 to