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- exceptions.Exception
-
- epicsMotorException
- epicsMotor
class epicsMotor |
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This module provides a class library for the EPICS motor record.
It uses the epicsPV class, which is in turn a subclass of CaChannel.
Virtual attributes:
These attributes do not appear in the dictionary for this class, but
are implemented with the __getattr__ and __setattr__ methods. They
simply do getw() or putw(value) to the appropriate motor record fields.
All attributes can be both read and written unless otherwise noted.
Attribute Description Field
--------- ----------------------- -----
slew_speed Slew speed or velocity .VELO
base_speed Base or starting speed .VBAS
acceleration Acceleration time (sec) .ACCL
description Description of motor .DESC
resolution Resolution (units/step) .MRES
high_limit High soft limit (user) .HLM
low_limit Low soft limit (user) .LLM
dial_high_limit High soft limit (dial) .DHLM
dial_low_limit Low soft limit (dial) .DLLM
backlash Backlash distance .BDST
offset Offset from dial to user .OFF
done_moving 1=Done, 0=Moving, read-only .DMOV
Exceptions:
The check_limits() method raises an "epicsMotorException" if a soft limit
or hard limit is detected. The move() and wait() methods call
check_limits() before they return, unless they are called with the
ignore_limits=1 keyword set.
Example use:
from epicsMotor import *
m=epicsMotor('13BMD:m38')
m.move(10) # Move to position 10 in user coordinates
m.move(100, dial=1) # Move to position 100 in dial coordinates
m.move(1, step=1, relative=1) # Move 1 step relative to current position
m.wait() # Wait for motor to stop moving
m.wait(start=1) # Wait for motor to start moving
m.wait(start=1, stop=1) # Wait for motor to start, then to stop
m.stop() # Stop moving immediately
high = m.high_limit # Get the high soft limit in user coordinates
m.dial_high_limit = 100 # Set the high limit to 100 in dial coodinates
speed = m.slew_speed # Get the slew speed
m.acceleration = 0.1 # Set the acceleration to 0.1 seconds
p=m.get_position() # Get the desired motor position in user coordinates
p=m.get_position(dial=1) # Get the desired motor position in dial coordinates
p=m.get_position(readback=1) # Get the actual position in user coordinates
p=m.get_position(readback=1, step=1) Get the actual motor position in steps
p=m.set_position(100) # Set the current position to 100 in user coordinates
# Puts motor in Set mode, writes value, puts back in Use mode.
p=m.set_position(10000, step=1) # Set the current position to 10000 steps
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Methods defined here:
- __getattr__(self, attrname)
- __init__(self, name)
- Creates a new epicsMotor instance.
Inputs:
name:
The name of the EPICS motor record without any trailing period or field
name.
Example:
m=epicsMotor('13BMD:m38')
- __setattr__(self, attrname, value)
- check_limits(self)
- get_position(self, dial=0, readback=0, step=0)
- Returns the target or readback motor position in user, dial or step
coordinates.
Keywords:
readback:
Set readback=1 to return the readback position in the
desired coordinate system. The default is to return the
target position of the motor.
dial:
Set dial=1 to return the position in dial coordinates.
The default is user coordinates.
step:
Set step=1 to return the position in steps.
The default is user coordinates.
Notes:
The "step" and "dial" keywords are mutually exclusive.
The "readback" keyword can be used in user, dial or step
coordinates.
Examples:
m=epicsMotor('13BMD:m38')
m.move(10) # Move to position 10 in user coordinates
p=m.get_position(dial=1) # Read the target position in
# dial coordinates
p=m.get_position(readback=1, step=1) # Read the actual position in
# steps
- move(self, value, relative=0, dial=0, step=0, ignore_limits=0)
- Moves a motor to an absolute position or relative to the current position
in user, dial or step coordinates.
Inputs:
value:
The absolute position or relative amount of the move
Keywords:
relative:
Set relative=1 to move relative to current position.
The default is an absolute move.
dial:
Set dial=1 if "value" is in dial coordinates.
The default is user coordinates.
step:
Set step=1 if "value" is in steps.
The default is user coordinates.
ignore_limits:
Set ignore_limits=1 to suppress raising exceptions
if the move results in a soft or hard limit violation.
Notes:
The "step" and "dial" keywords are mutually exclusive.
The "relative" keyword can be used in user, dial or step
coordinates.
Examples:
m=epicsMotor('13BMD:m38')
m.move(10) # Move to position 10 in user coordinates
m.move(100, dial=1) # Move to position 100 in dial coordinates
m.move(2, step=1, relative=1) # Move 2 steps
- set_position(self, position, dial=0, step=0)
- Sets the motor position in user, dial or step coordinates.
Inputs:
position:
The new motor position
Keywords:
dial:
Set dial=1 to set the position in dial coordinates.
The default is user coordinates.
step:
Set step=1 to set the position in steps.
The default is user coordinates.
Notes:
The "step" and "dial" keywords are mutually exclusive.
Examples:
m=epicsMotor('13BMD:m38')
m.set_position(10, dial=1) # Set the motor position to 10 in
# dial coordinates
m.set_position(1000, step=1) # Set the motor position to 1000 steps
- stop(self)
- Immediately stops a motor from moving by writing 1 to the .STOP field.
Examples:
m=epicsMotor('13BMD:m38')
m.move(10) # Move to position 10 in user coordinates
m.stop() # Stop motor
- wait(self, start=0, stop=0, poll=0.01, ignore_limits=0)
- Waits for the motor to start moving and/or stop moving.
Keywords:
start:
Set start=1 to wait for the motor to start moving.
stop:
Set stop=1 to wait for the motor to stop moving.
poll:
Set this keyword to the time to wait between reading the
.DMOV field of the record to see if the motor is moving.
The default is 0.01 seconds.
ignore_limits:
Set ignore_limits=1 to suppress raising an exception if a soft or
hard limit is detected
Notes:
If neither the "start" nor "stop" keywords are set then "stop"
is set to 1, so the routine waits for the motor to stop moving.
If only "start" is set to 1 then the routine only waits for the
motor to start moving.
If both "start" and "stop" are set to 1 then the routine first
waits for the motor to start moving, and then to stop moving.
Examples:
m=epicsMotor('13BMD:m38')
m.move(100) # Move to position 100
m.wait(start=1, stop=1) # Wait for the motor to start moving
# and then to stop moving
Data and non-method functions defined here:
- __doc__ = '\n This module provides a class library for the...tep=1) # Set the current position to 10000 steps\n'
- str(object) -> string
Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
- __module__ = 'epicsMotor'
- str(object) -> string
Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
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