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Technical Support
E-mail: support@stepcontrol.com
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Step
Motor Precautions
Stepping (or step,
or stepper) motors are simple rugged devices and are
generally immune from:
A. Stall Condition-
when the motor shaft is locked and the drivers continue to attempt to rotate it,
the motor current is actually reduced, preventing damage. Stall's from
operation at the natural resonance's step rates will similarly not result in
damage. Note, that if these conditions persist with use of a high performance
chopper, excessive heating could occur.
B. High Currents -
as long as the motor DOES NOT overheat it takes extremely high current to
damage the magnets. A step motor can be driven with high current or high voltage
power chopper drives, provided that it is not allowed to over heat.
Most stepping motors can
withstand 100 degree C. temperatures without damage. Excessive heat will melt
insulating materials and cause the motor to freeze up beyond repair.
Factors that must be considered include duty cycle, thermal time constant, heat
conduction (sinking) to the system, ambient temperatures and air flow. As a rule
of thumb (ROT) if you can hold onto the motor, than it isn't too hot.
Education
The following websites can provide useful engineering information. We
have no control of their content or future. They were in existence as of
these dates.
Control of Stepping Motors (a
tutorial): 10/99
http://www.cs.uiowa.edu/~jones/step/index.html
Step Motor Reference Guide (400K)
This complete copy of the reference guide is available in PDF format
Interfacing a Mac Serial Port to RS232 Lab Equipment 01/00
http://www.mindspring.com/~jc1/serial/main.html
Command Set
This is a typical command set for Advanced Micro Systems
intelligent step motor controllers. Some variations are used for different
drives. See the data sheet
manual for the specific controller.
| Commands for SMC |
Encoder
commands |
| ASCII |
Description
|
ASCII |
Description
|
| ESC |
Abort/Terminate
|
|
|
| @ |
Soft Stop
|
|
|
| ^C |
Reset
|
|
|
| + |
Index in Plus Direction
|
|
|
| - |
Index in Minus Direction
|
|
|
| [ |
Read NV Memory
|
|
|
| ] |
Read Limits, Hardware
|
|
|
| \ |
Write to NV Memory
|
|
|
| ^ |
Read Moving Status
|
|
|
| A |
Port Read/Write (optional)
|
a |
stall counter
|
| B |
Jog Speed, Slow/Fast (optional)
|
|
|
| C |
Restore/Initialize
|
c |
clear
driver
|
| D |
Divide Step Rates
|
d |
deadband enable
|
| E |
Enable Auto Power Down
|
e |
encoder
resolution
|
| F |
Find Home (SPS)
|
f |
find
encoder mark
|
| G |
GO from Address
|
|
|
| H |
Step
Resolution
|
h |
hunt
resolution
|
| I |
Initial Velocity
(SPS)
|
|
|
| J |
Jump to Address
|
j |
secondary
jump
|
| K |
Ramp Slope
|
k |
special
trip
|
| L |
Loop on Port (optional)
|
l |
limit
polarity
|
| M |
Move at a Constant Speed
|
|
|
| N |
|
n |
force
encoder position
|
| O |
Set Origin
|
o |
reset
origin 0
|
| P |
Program Mode
|
|
|
| Q |
Query Program
|
q |
query
program
|
| R |
Index to Target Position
|
r |
stall
retries
|
| S |
Store Parameters
|
s |
stall
detect
|
| T |
Set Trip Point
|
t |
stall
delta
|
| U |
|
|
|
| V |
Slew Velocity (SPS)
|
v |
hunt
velocity
|
| W |
Wait "N" Milliseconds
|
w |
read
driver stat
|
| X |
Examine Parameters
|
x |
examine
|
| Y |
Set
Currents
|
y |
carriage
return/line feed
|
| Z |
Display Position
|
z |
read
encoder position
|
This command set will vary from product to
product depending upon model and features. Encoder feedback is possible only with
micro step controller/driver
combinations. |
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