from __future__ import absolute_import from __future__ import division from __future__ import print_function from __future__ import unicode_literals import collections import ctypes import numpy import warnings from nidaqmx._lib import ( lib_importer, wrapped_ndpointer, ctypes_byte_str, c_bool32) from nidaqmx.errors import ( check_for_error, is_string_buffer_too_small, is_array_buffer_too_small, DaqResourceWarning) from nidaqmx.system._watchdog_modules.expiration_state import ExpirationState from nidaqmx.system._watchdog_modules.expiration_states_collection import ( ExpirationStatesCollection) from nidaqmx.utils import flatten_channel_string from nidaqmx.constants import ( Edge, TriggerType, WDTTaskAction) from nidaqmx.types import ( AOExpirationState, COExpirationState, DOExpirationState) __all__ = ['WatchdogTask'] class WatchdogTask(object): """ Represents the watchdog configurations for a DAQmx task. """ def __init__(self, device_name, task_name='', timeout=10): """ Creates and configures a task that controls the watchdog timer of a device. The timer activates when you start the task. Use the DAQmx Configure Watchdog Expiration States functions to configure channel expiration states. This class does not program the watchdog timer on a real-time controller. Args: device_name (str): Specifies is the name as configured in MAX of the device to which this operation applies. task_name (str): Specifies the name to assign to the task. If you use this constructor in a loop and specify a name for the task, you must use the DAQmx Clear Task method within the loop after you are finished with the task. Otherwise, NI-DAQmx attempts to create multiple tasks with the same name, which results in an error. timeout (float): Specifies the amount of time in seconds until the watchdog timer expires. A value of -1 means the internal timer never expires. Set this input to -1 if you use an Expiration Trigger to expire the watchdog task. If this time elapses, the device sets the physical channels to the states you specify with the digital physical channel expiration states input. """ self._handle = lib_importer.task_handle(0) cfunc = lib_importer.windll.DAQmxCreateWatchdogTimerTaskEx if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ ctypes_byte_str, ctypes_byte_str, ctypes.POINTER(lib_importer.task_handle), ctypes.c_double] error_code = cfunc( device_name, task_name, ctypes.byref(self._handle), timeout) check_for_error(error_code) # Saved name is used in self.close() to throw graceful error on # double closes. self._saved_name = self.name self._expiration_states = ExpirationStatesCollection(self._handle) def __del__(self): if self._handle is not None: warnings.warn( 'Task of name "{0}" was not explicitly closed before it was ' 'destructed. Resources on the task device may still be ' 'reserved.'.format(self.name), DaqResourceWarning) def __enter__(self): return self def __exit__(self, type, value, traceback): self.close() @property def expiration_states(self): """ nidaqmx.system._watchdog_modules.expiration_states_collection. ExpirationStatesCollection: Gets the collection of expiration states for this watchdog task. """ return self._expiration_states @property def expir_trig_dig_edge_edge(self): """ :class:`nidaqmx.constants.Edge`: Specifies on which edge of a digital signal to expire the watchdog task. """ val = ctypes.c_int() cfunc = lib_importer.windll.DAQmxGetDigEdgeWatchdogExpirTrigEdge if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.POINTER(ctypes.c_int)] error_code = cfunc( self._handle, ctypes.byref(val)) check_for_error(error_code) return Edge(val.value) @expir_trig_dig_edge_edge.setter def expir_trig_dig_edge_edge(self, val): val = val.value cfunc = lib_importer.windll.DAQmxSetDigEdgeWatchdogExpirTrigEdge if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_int] error_code = cfunc( self._handle, val) check_for_error(error_code) @expir_trig_dig_edge_edge.deleter def expir_trig_dig_edge_edge(self): cfunc = lib_importer.windll.DAQmxResetDigEdgeWatchdogExpirTrigEdge if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc( self._handle) check_for_error(error_code) @property def expir_trig_dig_edge_src(self): """ str: Specifies the name of a terminal where a digital signal exists to use as the source of the Expiration Trigger. """ cfunc = lib_importer.windll.DAQmxGetDigEdgeWatchdogExpirTrigSrc if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_char_p, ctypes.c_uint] temp_size = 0 while True: val = ctypes.create_string_buffer(temp_size) size_or_code = cfunc( self._handle, val, temp_size) if is_string_buffer_too_small(size_or_code): # Buffer size must have changed between calls; check again. temp_size = 0 elif size_or_code > 0 and temp_size == 0: # Buffer size obtained, use to retrieve data. temp_size = size_or_code else: break check_for_error(size_or_code) return val.value.decode('ascii') @expir_trig_dig_edge_src.setter def expir_trig_dig_edge_src(self, val): cfunc = lib_importer.windll.DAQmxSetDigEdgeWatchdogExpirTrigSrc if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes_byte_str] error_code = cfunc( self._handle, val) check_for_error(error_code) @expir_trig_dig_edge_src.deleter def expir_trig_dig_edge_src(self): cfunc = lib_importer.windll.DAQmxResetDigEdgeWatchdogExpirTrigSrc if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc( self._handle) check_for_error(error_code) @property def expir_trig_trig_on_network_conn_loss(self): """ bool: Specifies the watchdog timer behavior when the network connection is lost between the host and the chassis. If set to true, the watchdog timer expires when the chassis detects the loss of network connection. """ val = c_bool32() cfunc = (lib_importer.windll. DAQmxGetWatchdogExpirTrigOnNetworkConnLoss) if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.POINTER(c_bool32)] error_code = cfunc( self._handle, ctypes.byref(val)) check_for_error(error_code) return val.value @expir_trig_trig_on_network_conn_loss.setter def expir_trig_trig_on_network_conn_loss(self, val): cfunc = (lib_importer.windll. DAQmxSetWatchdogExpirTrigOnNetworkConnLoss) if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, c_bool32] error_code = cfunc( self._handle, val) check_for_error(error_code) @expir_trig_trig_on_network_conn_loss.deleter def expir_trig_trig_on_network_conn_loss(self): cfunc = (lib_importer.windll. DAQmxResetWatchdogExpirTrigOnNetworkConnLoss) if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc( self._handle) check_for_error(error_code) @property def expir_trig_trig_type(self): """ :class:`nidaqmx.constants.TriggerType`: Specifies the type of trigger to use to expire a watchdog task. """ val = ctypes.c_int() cfunc = lib_importer.windll.DAQmxGetWatchdogExpirTrigType if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.POINTER(ctypes.c_int)] error_code = cfunc( self._handle, ctypes.byref(val)) check_for_error(error_code) return TriggerType(val.value) @expir_trig_trig_type.setter def expir_trig_trig_type(self, val): val = val.value cfunc = lib_importer.windll.DAQmxSetWatchdogExpirTrigType if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_int] error_code = cfunc( self._handle, val) check_for_error(error_code) @expir_trig_trig_type.deleter def expir_trig_trig_type(self): cfunc = lib_importer.windll.DAQmxResetWatchdogExpirTrigType if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc( self._handle) check_for_error(error_code) @property def expired(self): """ bool: Indicates if the watchdog timer expired. You can read this property only while the task is running. """ val = c_bool32() cfunc = lib_importer.windll.DAQmxGetWatchdogHasExpired if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.POINTER(c_bool32)] error_code = cfunc( self._handle, ctypes.byref(val)) check_for_error(error_code) return val.value @property def timeout(self): """ float: Specifies in seconds the amount of time until the watchdog timer expires. A value of -1 means the internal timer never expires. Set this input to -1 if you use an Expiration Trigger to expire the watchdog task. """ val = ctypes.c_double() cfunc = lib_importer.windll.DAQmxGetWatchdogTimeout if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.POINTER(ctypes.c_double)] error_code = cfunc( self._handle, ctypes.byref(val)) check_for_error(error_code) return val.value @timeout.setter def timeout(self, val): cfunc = lib_importer.windll.DAQmxSetWatchdogTimeout if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_double] error_code = cfunc( self._handle, val) check_for_error(error_code) @timeout.deleter def timeout(self): cfunc = lib_importer.windll.DAQmxResetWatchdogTimeout if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc( self._handle) check_for_error(error_code) @property def name(self): """ str: Indicates the name of the task. """ cfunc = lib_importer.windll.DAQmxGetTaskName if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_char_p, ctypes.c_uint] temp_size = 0 while True: val = ctypes.create_string_buffer(temp_size) size_or_code = cfunc( self._handle, val, temp_size) if is_string_buffer_too_small(size_or_code): # Buffer size must have changed between calls; check again. temp_size = 0 elif size_or_code > 0 and temp_size == 0: # Buffer size obtained, use to retrieve data. temp_size = size_or_code else: break check_for_error(size_or_code) return val.value.decode('ascii') def _control_watchdog_task(self, action): """ Controls the watchdog timer task according to the action you specify. This function does not program the watchdog timer on a real-time controller. Use the Real-Time Watchdog VIs to program the watchdog timer on a real-time controller. Args: action (nidaqmx.constants.WDTTaskAction): Specifies how to control the watchdog timer task. """ cfunc = lib_importer.windll.DAQmxControlWatchdogTask if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_int] error_code = cfunc( self._handle, action.value) check_for_error(error_code) def cfg_watchdog_ao_expir_states(self, expiration_states): """ Configures the expiration states for an analog watchdog timer task. Args: expiration_states (List[nidaqmx.system.watchdog.AOExpirationState]): Contains the states to which to set analog physical channels when the watchdog timer expires. Each element of the list contains an analog physical channel name, the corresponding expiration state, and the output type for that analog physical channel. The units of "expiration state" must be specified in volts for an analog output voltage expiration state, or amps for an analog output current expiration state. physical_channel (str): Specifies the analog output channel to modify. You cannot modify dedicated analog input lines. expiration_state (float): Specifies the value to set the channel to upon expiration. output_type (nidaqmx.constants.WatchdogAOExpirState): Specifies the output type of the physical channel. Returns: List[nidaqmx.system._watchdog_modules.expiration_state.ExpirationState]: Indicates the list of objects representing the configured expiration states. """ channel_names = flatten_channel_string( [e.physical_channel for e in expiration_states]) expir_state = numpy.float64( [e.expiration_state for e in expiration_states]) output_type = numpy.int32( [e.output_type.value for e in expiration_states]) cfunc = lib_importer.windll.DAQmxCfgWatchdogAOExpirStates if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes_byte_str, wrapped_ndpointer(dtype=numpy.float64, flags=('C', 'W')), wrapped_ndpointer(dtype=numpy.int32, flags=('C', 'W')), ctypes.c_uint] error_code = cfunc( self._handle, channel_names, expir_state, output_type, len(expiration_states)) check_for_error(error_code) return [ExpirationState(self._handle, e.physical_channel) for e in expiration_states] def cfg_watchdog_co_expir_states(self, expiration_states): """ Configures the expiration states for a counter watchdog timer task. Args: expiration_states (List[nidaqmx.system.watchdog.COExpirationState]): Contains the states to which to set counter physical channels when the watchdog timer expires. Each element of the list contains a counter physical channel name and the corresponding state for that counter physical channel. physical_channel (str): Specifies the counter output channel to modify. You cannot modify dedicated counter input lines. expiration_state (nidaqmx.constants.WatchdogCOExpirState): Specifies the value to set the channel to upon expiration. Returns: List[nidaqmx.system._watchdog_modules.expiration_state.ExpirationState]: Indicates the list of objects representing the configured expiration states. """ channel_names = flatten_channel_string( [e.physical_channel for e in expiration_states]) expir_state = numpy.int32( [e.expiration_state.value for e in expiration_states]) cfunc = lib_importer.windll.DAQmxCfgWatchdogCOExpirStates if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes_byte_str, wrapped_ndpointer(dtype=numpy.int32, flags=('C', 'W')), ctypes.c_uint] error_code = cfunc( self._handle, channel_names, expir_state, len(expiration_states)) check_for_error(error_code) return [ExpirationState(self._handle, e.physical_channel) for e in expiration_states] def cfg_watchdog_do_expir_states(self, expiration_states): """ Configures the expiration states for a digital watchdog timer task. Args: expiration_states (List[nidaqmx.system.watchdog.DOExpirationState]): Contains the states to which to set digital physical channels when the watchdog timer expires. Each element of the list contains a digital physical channel name and the corresponding state for that digital physical channel. physical_channel (str): Specifies the digital output channel to modify. You cannot modify dedicated digital input lines. expiration_state (nidaqmx.constants.Level): Specifies the value to set the channel to upon expiration. Returns: List[nidaqmx.system._watchdog_modules.expiration_state.ExpirationState]: Indicates the list of objects representing the configured expiration states. """ channel_names = flatten_channel_string( [e.physical_channel for e in expiration_states]) expir_state = numpy.int32( [e.expiration_state.value for e in expiration_states]) cfunc = lib_importer.windll.DAQmxCfgWatchdogDOExpirStates if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes_byte_str, wrapped_ndpointer(dtype=numpy.int32, flags=('C', 'W')), ctypes.c_uint] error_code = cfunc( self._handle, channel_names, expir_state, len(expiration_states)) check_for_error(error_code) return [ExpirationState(self._handle, e.physical_channel) for e in expiration_states] def clear_expiration(self): """ Unlock a device whose watchdog timer expired. This function does not program the watchdog timer on a real-time controller. Use the Real-Time Watchdog VIs to program the watchdog timer on a real-time controller. """ self._control_watchdog_task(WDTTaskAction.CLEAR_EXPIRATION) def close(self): """ Clears the task. Before clearing, this method aborts the task, if necessary, and releases any resources the task reserved. You cannot use a task after you clear it unless you recreate the task. If you create a DAQmx Task object within a loop, use this method within the loop after you are finished with the task to avoid allocating unnecessary memory. """ if self._handle is None: warnings.warn( 'Attempted to close NI-DAQmx task of name "{0}" but task was ' 'already closed.'.format(self._saved_name), DaqResourceWarning) return cfunc = lib_importer.windll.DAQmxClearTask if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle] error_code = cfunc(self._handle) check_for_error(error_code) self._handle = None def control(self, action): """ Alters the state of a task according to the action you specify. Args: action (nidaqmx.constants.TaskMode): Specifies how to alter the task state. """ cfunc = lib_importer.windll.DAQmxTaskControl if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ lib_importer.task_handle, ctypes.c_int] error_code = cfunc( self._handle, action.value) check_for_error(error_code) def reset_timer(self): """ Reset the internal timer. You must continually reset the internal timer to prevent it from timing out and locking the device. This function does not program the watchdog timer on a real-time controller. Use the Real-Time Watchdog VIs to program the watchdog timer on a real-time controller. """ self._control_watchdog_task(WDTTaskAction.RESET_TIMER) def start(self): """ Transitions the task to the running state to begin the measurement or generation. Using this method is required for some applications and is optional for others. """ cfunc = lib_importer.windll.DAQmxStartTask if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [lib_importer.task_handle] error_code = cfunc(self._handle) check_for_error(error_code) def stop(self): """ Stops the task and returns it to the state the task was in before the DAQmx Start Task method ran. """ cfunc = lib_importer.windll.DAQmxStopTask if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [lib_importer.task_handle] error_code = cfunc(self._handle) check_for_error(error_code)