LM629N-8 National Semiconductor, LM629N-8 Datasheet - Page 15

• Manufacturer Part Number: LM629N-8
• Description: IC,Motor Controller,MOS,DIP,28PIN
• Manufacturer: National Semiconductor

Specifications of LM629N-8

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Note 8: Sampling intervals shown are when using an 8.0 MHz clock. The 256 corresponds to 2048/8 MHz; sample intervals must be scaled for other clock frequen-
cies.
Filter Control Commands
The UDF command is used to update the filter parameters,
the specifics of which have been programmed via the LFIL
command. Any or all parameters (derivative-term sampling
interval, kp, ki, kd, and/or il) may be changed by the appro-
priate command(s), but command UDF must be executed to
affect the change in filter tuning. Filter updating is synchro-
nized with the calculations to eliminate erratic or spurious
behavior.
Trajectory Control Commands
The following two LM628 user commands are used for set-
ting the trajectory control parameters (position, velocity, ac-
celeration), mode of operation (position or velocity), and di-
rection (velocity mode only) as required to describe a
desired motion or to select the mode of a manually directed
stop, and to control the timing of these system changes.
The trajectory control parameters which are written to the
LM628 to control motion are: acceleration, velocity, and po-
sition. In addition, indications as to whether these three pa-
rameters are to be considered as absolute or relative inputs,
selection of velocity mode and direction, and manual stop-
ping mode selection and execution are programmable via
this command. After writing the command code, the first two
data bytes that are written specify which parameter(s) is/are
being changed. The first byte written is the more significant.
Thus the two data bytes constitute a trajectory control word
that informs the LM628 as to the nature and number of any
following data bytes. See Table 6 .
Bit Position
Executable During Motion: Yes
TABLE 6. Trajectory Control Word Bit Allocation
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
15
0
0
0
0
1
Stop Abruptly (Maximum Deceleration)
Turn Off Motor (Output Zero Drive)
Not Used
Not Used
Not Used
Not Used
Not Used
Forward Direction (Velocity Mode Only)
Velocity Mode
Stop Smoothly (Decelerate as
Programmed)
14
0
0
0
0
1
TABLE 5. Derivative-Term Sampling Interval Selection Codes
Function
13
0
0
0
0
1
Bit Position
(Continued)
12
0
0
0
0
1
11
0
0
0
0
1
15
LTRJ COMMAND: Load TRaJectory Parameters
Bit 12 determines the motor direction when in the velocity
mode. A logic one indicates forward direction. This bit has no
effect when in position mode.
Bit 11 determines whether the LM628 operates in velocity
mode (Bit 11 logic one) or position mode (Bit 11 logic zero).
Bits 8 through 10 are used to select the method of manually
stopping the motor. These bits are not provided for one to
merely specify the desired mode of stopping, in position
mode operations, normal stopping is always smooth and oc-
curs automatically at the end of the specified trajectory. Un-
der exceptional circumstances it may be desired to manually
intervene with the trajectory generation process to affect a
premature stop. In velocity mode operations, however, the
normal means of stopping is via bits 8 through 10 (usually bit
10). Bit 8 is set to logic one to stop the motor by turning off
motor drive output (outputting the appropriate offset-binary
code to apply zero drive to the motor); bit 9 is set to one to
stop the motor abruptly (at maximum available acceleration,
by setting the target position equal to the current position);
and bit 10 is set to one to stop the motor smoothly by using
Bit Position
Command Code:
Data Bytes:
Data Ranges…
Acceleration:
Executable During
Trajectory Control
Position:
Velocity:
Motion:
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
10
0
0
0
0
1
Word:
9
0
0
1
1
1
Acceleration Will Be Loaded
Acceleration Data Is Relative
Velocity Will Be Loaded
Velocity Data Is Relative
Position Will Be Loaded
Position Data Is Relative
8
0
1
0
1
1
1F Hex
Two to Fourteen
See Text
C0000000 to 3FFFFFFF Hex
00000000 to 3FFFFFFF Hex
(Pos Only)
00000000 to 3FFFFFFF Hex
(Pos Only)
Conditionally, See Text
Function
65,536 µs
1024 µs, etc…
Selected Derivative
256 µs
512 µs
768 µs
Sampling Interval
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