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yocto_quadraturedecoder.py
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yocto_quadraturedecoder.py
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#*********************************************************************
#*
#* $Id: yocto_quadraturedecoder.py 23243 2016-02-23 14:13:12Z seb $
#*
#* Implements yFindQuadratureDecoder(), the high-level API for QuadratureDecoder functions
#*
#* - - - - - - - - - License information: - - - - - - - - -
#*
#* Copyright (C) 2011 and beyond by Yoctopuce Sarl, Switzerland.
#*
#* Yoctopuce Sarl (hereafter Licensor) grants to you a perpetual
#* non-exclusive license to use, modify, copy and integrate this
#* file into your software for the sole purpose of interfacing
#* with Yoctopuce products.
#*
#* You may reproduce and distribute copies of this file in
#* source or object form, as long as the sole purpose of this
#* code is to interface with Yoctopuce products. You must retain
#* this notice in the distributed source file.
#*
#* You should refer to Yoctopuce General Terms and Conditions
#* for additional information regarding your rights and
#* obligations.
#*
#* THE SOFTWARE AND DOCUMENTATION ARE PROVIDED 'AS IS' WITHOUT
#* WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
#* WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS
#* FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO
#* EVENT SHALL LICENSOR BE LIABLE FOR ANY INCIDENTAL, SPECIAL,
#* INDIRECT OR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA,
#* COST OF PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR
#* SERVICES, ANY CLAIMS BY THIRD PARTIES (INCLUDING BUT NOT
#* LIMITED TO ANY DEFENSE THEREOF), ANY CLAIMS FOR INDEMNITY OR
#* CONTRIBUTION, OR OTHER SIMILAR COSTS, WHETHER ASSERTED ON THE
#* BASIS OF CONTRACT, TORT (INCLUDING NEGLIGENCE), BREACH OF
#* WARRANTY, OR OTHERWISE.
#*
#*********************************************************************/
__docformat__ = 'restructuredtext en'
from yocto_api import *
#--- (YQuadratureDecoder class start)
#noinspection PyProtectedMember
class YQuadratureDecoder(YSensor):
"""
The class YQuadratureDecoder allows you to decode a two-wire signal produced by a
quadrature encoder. It inherits from YSensor class the core functions to read measurements,
register callback functions, access to the autonomous datalogger.
"""
#--- (end of YQuadratureDecoder class start)
#--- (YQuadratureDecoder return codes)
#--- (end of YQuadratureDecoder return codes)
#--- (YQuadratureDecoder dlldef)
#--- (end of YQuadratureDecoder dlldef)
#--- (YQuadratureDecoder definitions)
SPEED_INVALID = YAPI.INVALID_DOUBLE
DECODING_OFF = 0
DECODING_ON = 1
DECODING_INVALID = -1
#--- (end of YQuadratureDecoder definitions)
def __init__(self, func):
super(YQuadratureDecoder, self).__init__(func)
self._className = 'QuadratureDecoder'
#--- (YQuadratureDecoder attributes)
self._callback = None
self._speed = YQuadratureDecoder.SPEED_INVALID
self._decoding = YQuadratureDecoder.DECODING_INVALID
#--- (end of YQuadratureDecoder attributes)
#--- (YQuadratureDecoder implementation)
def _parseAttr(self, member):
if member.name == "speed":
self._speed = round(member.ivalue * 1000.0 / 65536.0) / 1000.0
return 1
if member.name == "decoding":
self._decoding = member.ivalue
return 1
super(YQuadratureDecoder, self)._parseAttr(member)
def set_currentValue(self, newval):
"""
Changes the current expected position of the quadrature decoder.
Invoking this function implicitely activates the quadrature decoder.
@param newval : a floating point number corresponding to the current expected position of the quadrature decoder
@return YAPI.SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
"""
rest_val = str(int(round(newval * 65536.0, 1)))
return self._setAttr("currentValue", rest_val)
def get_speed(self):
"""
Returns the PWM frequency in Hz.
@return a floating point number corresponding to the PWM frequency in Hz
On failure, throws an exception or returns YQuadratureDecoder.SPEED_INVALID.
"""
if self._cacheExpiration <= YAPI.GetTickCount():
if self.load(YAPI.DefaultCacheValidity) != YAPI.SUCCESS:
return YQuadratureDecoder.SPEED_INVALID
return self._speed
def get_decoding(self):
"""
Returns the current activation state of the quadrature decoder.
@return either YQuadratureDecoder.DECODING_OFF or YQuadratureDecoder.DECODING_ON, according to the
current activation state of the quadrature decoder
On failure, throws an exception or returns YQuadratureDecoder.DECODING_INVALID.
"""
if self._cacheExpiration <= YAPI.GetTickCount():
if self.load(YAPI.DefaultCacheValidity) != YAPI.SUCCESS:
return YQuadratureDecoder.DECODING_INVALID
return self._decoding
def set_decoding(self, newval):
"""
Changes the activation state of the quadrature decoder.
@param newval : either YQuadratureDecoder.DECODING_OFF or YQuadratureDecoder.DECODING_ON, according
to the activation state of the quadrature decoder
@return YAPI.SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
"""
rest_val = "1" if newval > 0 else "0"
return self._setAttr("decoding", rest_val)
@staticmethod
def FindQuadratureDecoder(func):
"""
Retrieves a quadrature decoder for a given identifier.
The identifier can be specified using several formats:
<ul>
<li>FunctionLogicalName</li>
<li>ModuleSerialNumber.FunctionIdentifier</li>
<li>ModuleSerialNumber.FunctionLogicalName</li>
<li>ModuleLogicalName.FunctionIdentifier</li>
<li>ModuleLogicalName.FunctionLogicalName</li>
</ul>
This function does not require that the quadrature decoder is online at the time
it is invoked. The returned object is nevertheless valid.
Use the method YQuadratureDecoder.isOnline() to test if the quadrature decoder is
indeed online at a given time. In case of ambiguity when looking for
a quadrature decoder by logical name, no error is notified: the first instance
found is returned. The search is performed first by hardware name,
then by logical name.
@param func : a string that uniquely characterizes the quadrature decoder
@return a YQuadratureDecoder object allowing you to drive the quadrature decoder.
"""
# obj
obj = YFunction._FindFromCache("QuadratureDecoder", func)
if obj is None:
obj = YQuadratureDecoder(func)
YFunction._AddToCache("QuadratureDecoder", func, obj)
return obj
def nextQuadratureDecoder(self):
"""
Continues the enumeration of quadrature decoders started using yFirstQuadratureDecoder().
@return a pointer to a YQuadratureDecoder object, corresponding to
a quadrature decoder currently online, or a None pointer
if there are no more quadrature decoders to enumerate.
"""
hwidRef = YRefParam()
if YAPI.YISERR(self._nextFunction(hwidRef)):
return None
if hwidRef.value == "":
return None
return YQuadratureDecoder.FindQuadratureDecoder(hwidRef.value)
#--- (end of YQuadratureDecoder implementation)
#--- (QuadratureDecoder functions)
@staticmethod
def FirstQuadratureDecoder():
"""
Starts the enumeration of quadrature decoders currently accessible.
Use the method YQuadratureDecoder.nextQuadratureDecoder() to iterate on
next quadrature decoders.
@return a pointer to a YQuadratureDecoder object, corresponding to
the first quadrature decoder currently online, or a None pointer
if there are none.
"""
devRef = YRefParam()
neededsizeRef = YRefParam()
serialRef = YRefParam()
funcIdRef = YRefParam()
funcNameRef = YRefParam()
funcValRef = YRefParam()
errmsgRef = YRefParam()
size = YAPI.C_INTSIZE
#noinspection PyTypeChecker,PyCallingNonCallable
p = (ctypes.c_int * 1)()
err = YAPI.apiGetFunctionsByClass("QuadratureDecoder", 0, p, size, neededsizeRef, errmsgRef)
if YAPI.YISERR(err) or not neededsizeRef.value:
return None
if YAPI.YISERR(
YAPI.yapiGetFunctionInfo(p[0], devRef, serialRef, funcIdRef, funcNameRef, funcValRef, errmsgRef)):
return None
return YQuadratureDecoder.FindQuadratureDecoder(serialRef.value + "." + funcIdRef.value)
#--- (end of QuadratureDecoder functions)

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