Logosol Absolute Positioning Servo Drive LS-173AP
Doc # 712173008 / Rev. 1.06, 05/09/2002
Logosol, Inc.
••
1155 Tasman Drive
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Sunnyvale, CA 94089 Tel: (408) 744-0974
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www.logosolinc.com 25
initiated or if the velocity profiler is used. Trapezoidal profile motions should only be initialized
when the motor velocity is 0. (Bit 0 of the status byte indicates when a trapezoidal profile
motion has been completed, or in velocity mode, when the command velocity has been
reached.) Bit 6 indicates the velocity or PWM direction and is ignored in trapezoidal profile
mode. If bit 7 is set, the command will be executed immediately. If bit 7 is clear, the command
data will be buffered, and it will be executed when the
Start Motion
command is issued. For
example to load only new position data and acceleration data but not to start the motion yet,
the command byte would be 0x94, the control byte would be 0x15, followed by 4 bytes of
position data (least significant byte first), followed by 4 bytes of acceleration data. If in the
middle of a trapezoidal position move, a new
Load Trajectory
command is issued with new
position data downloaded, new position data will be used as a relative offset to modify the
goal position. For example, if in the middle of a move to position 50,000, a new
Load
Trajectory
command with new position data of 10,000 is loaded, the motor will stop at final
position of 60,000. The relative offset can be either positive or negative. The new
Load
Trajectory
command must be issued while the motor is running at a constant velocity –
issuing the command while accelerating or decelerating will cause a position error to occur. If
more than one
Load Trajectory
is issued before the end of move, the goal position will be
modified by the sum of relative offsets.
Start Motion
Command value: 0x5
Number of data bytes: 0
Command byte:
0x05
Description:
Causes the trajectory information loaded with the most recent Load Trajectory command to
execute. This is useful for loading several Drives with trajectory information and then starting
them simultaneously with a group command.
Set Gain
Command value: 0x6
Number of data bytes: 14
Command byte:
0xE6
Data bytes:
1,2. Position gain KP (0 - 0x7FFF)
3,4. Velocity gain KD (0 - 0x7FFF)
5,6 Integral gain KI (0 - 0x7FFF)
7,8. Integration limit IL (0 - 0x7FFF)
9. Output limit OL (0 - 0xFF) (typically recommended 0xFA)
10. Not used. Must be set to 0.
11,12 Position error limit EL (0 - 0x3FFF)
13. Servo rate divisor SR (1 - 0xFF)
14. Amplifier deadband compensation (0 - 0xFF) (typical value is between 0x03 and
0x05)
Description:
Sets all parameters and limits governing the behavior of the position servo. KP, KD, KI and IL
are PID filter parameters. OL limits the maximal PWM output value to 0<PWM
≤
OL in position
servo modes. In PWM mode OL is ignored. The position error limit (EL) will cause the
position servo to be disabled should the position error grow beyond the limit. The servo rate
divisor sets the servo tick time to be a multiple of 0.512 msec (1.953 KHz). For example
SR=3 gives a servo rate of 651 Hz. The servo tick rate is also used as the profiling timebase,
although command processing, and current limiting are always performed at the maximum
