def send_command(self, address, command, data=None):
"""Sends a command to the sensor's address specified. The command
can optionally contain a data string.
This method is mostly for internal use, as the higher-level API is
exposed via dedicated methods.
Parameters
----------
address : :obj:`int`
PosCon3D sensors have an address assigned, which defaults to 1.
There's also a broadcast address (``PosCon3D.BROADCAST_ADDRESS``)
that can be used to query the address of the sensor connected to
the RS-485 bus. Only one sensor can be in the bus when using the
broadcast address to query for sensor's address.
command : :obj:`string`
A string indicating the command number to be executed.
data : :obj:`string`
An optional string of data that is sent together with
the command.
Returns
-------
`list` or value
Result of the command. It can be a list or a single value depending on the operation.
"""
cmd = self.format_command(address, command, data)
# Python 2 vs 3
if hasattr(cmd, 'decode'):
self.serial.write(cmd)
result = self.serial.readline()
else:
self.serial.write(cmd.encode('ascii'))
result = self.serial.readline().decode('ascii')
if result:
frame_head = result[:-4]
checksum = result[-4:-1]
expected = self.calculate_checksum(frame_head)
if expected != checksum:
raise ProtocolError(
'Invalid response, checksum mismatch. Expected=%s, Got=%s'
% (expected, checksum))
expected_frame_head = self.FRAME_HEAD % (address, command, '')
if not result.startswith(expected_frame_head):
raise ProtocolError(
'Invalid response, command/address mismatch. Expected to start with="%s", Got="%s"'
% (expected_frame_head, result))
return self.get_payload(result)
return None
def set_measurement_type(self, measurement_type):
"""Defines the measurement type to use.
=================== ======
Measurement type Value
=================== ======
"Diameter" 28
"X-Center position" 29
"Z-Center position" 30
"X-Left position" 31
"X-Right position" 32
"Z-Top position" 33
=================== ======
Parameters
----------
measurement_type : :obj:`string`
Measurement type.
"""
if measurement_type not in self.MEASUREMENT_TYPES:
raise ProtocolError('Unsupported measure type, must be one of ' +
str(self.MEASUREMENT_TYPES))
return self.send_command(self.address, 'W020',
str(self.MEASUREMENT_TYPES[measurement_type]))
def set_measurement_type(self, measurement_type):
"""Defines the measurement type to use.
=================== =========== ======
Measurement type Function Value
=================== =========== ======
"Edge L rise" Edge 0
"Edge L fall" Edge 1
"Edge R rise" Edge 2
"Edge R fall" Edge 3
"Width" Width 4
"Center width" Width 5
"Gap" Gap 6
"Center gap" Gap 7
=================== =========== ======
Parameters
----------
measurement_type : :obj:`string`
Measurement type.
"""
if measurement_type not in self.MEASUREMENT_TYPES:
raise ProtocolError('Unsupported measure type, must be one of ' +
str(self.MEASUREMENT_TYPES))
return self.send_command(
self.address, '020',
str(self.MEASUREMENT_TYPES.index(measurement_type)))
def set_measurement_type(self, measurement_type):
"""Defines the measurement type to use.
================ ========
Measurement type Function
================ ========
"Edge L rise" Edge
"Edge L fall" Edge
"Edge R rise" Edge
"Edge R fall" Edge
"Width" Width
"Center width" Width
"Gap" Gap
"Center gap" Gap
================ ========
Args:
measurement_type (:obj:`string`): Measurement type.
"""
if measurement_type not in self.MEASUREMENT_TYPES:
raise ProtocolError('Unsupported measure type, must be one of ' +
str(self.MEASUREMENT_TYPES))
return self.send_command(
self.address, '020',
str(self.MEASUREMENT_TYPES.index(measurement_type)))
def get_payload(self, result):
"""Gets payload."""
frame_head = result[:-6]
result_type = frame_head[3]
if result_type == 'a':
raise SensorTimeoutError('Sensor has not completed reading')
if result_type == 'E':
error_index = frame_head.split(';')
raise ProtocolError('Application error, Result=%s' % frame_head +
'Error type: ' +
str(self.ERROR_CODES[str(error_index[1])]))
if result_type == 'B':
raise ProtocolError('Sensor is busy, Result=%s' % frame_head)
return result[5:-6].split(';')
def get_measurement(self):
"""Retrieves the current measurement of the sensor according to the current settings.
Returns:
tuple: The current measurement and additionally a value indicating the quality of the measured value.
"""
result = self.send_command(self.address, '031')
if len(result) != 2:
raise ProtocolError('Unexpected result: ' + str(result))
return (result[0], self.QUALITY[int(result[1])])
def get_payload(result):
data = result.split(',')[2:-1]
if not data:
return None
elif len(data) == 1:
return data[0]
else:
if data[0] == 'E':
raise ProtocolError(ERROR_CODES[int(data[1])])
return data
def get_payload(self, result):
"""Gets payload."""
data = result.split(',')[2:-1]
if not data:
return None
elif len(data) == 1:
return data[0]
else:
if data[0] == 'E':
raise ProtocolError(self.ERROR_CODES[str(data[1])])
return data
def get_live_monitor_data(self):
"""Retrieves the distance to the surface in the center of the laser beam and the
angle at which it's found.
Returns:
list: angle and distance to the reference surface.
.. note::
This function is designed to aid in the installation of the sensor at an angle.
"""
result = self.send_command(self.address, '093')
if len(result) != 2:
raise ProtocolError('Unexpected result: ' + str(result))
return map(float, result)
def set_precision(self, precision):
"""Defines the precision the sensor will use to determine edges:
===== ========= ===============
Value Precision Function values
===== ========= ===============
``0`` Standard Median=off, Moving Average=off
``1`` High Median=7, Moving Average=16
``2`` Very High Median=15, Moving Average=128
===== ========= ===============
Args:
precision (:obj:`int`): Sensor precision to use.
.. note::
The higher the precision, the slower the measurement gets.
"""
if precision < 0 or precision > 2:
raise ProtocolError('Precision must be 0 (standard), 1 (high) or 2 (very high)')
return self.send_command(self.address, '040', str(precision))
def get_measurement(self):
"""Retrieves the current measurement of the sensor according to the current settings.
Returns
-------
`tuple`
The current measurement and additionally a value indicating the quality of the measured value.
"""
result = self.send_command(self.address, 'R021')
if len(result) != 3:
raise ProtocolError('Unexpected result: ' + str(result))
value = result[0]
quality = int(result[1])
# If Valid
if quality == 0:
value = float(value)
return (value, self.QUALITY[quality])