def query(self, cmd, size=-1):
"""
Executes the given query.
:param str cmd: String containing the query to
execute.
:param int size: Number of bytes to be read. Default is read until
termination character is found.
:return: The result of the query as returned by the
connected instrument.
:rtype: `str`
"""
ack_expected_list = self._ack_expected(cmd)
if not isinstance(ack_expected_list, (list, tuple)):
ack_expected_list = [ack_expected_list]
if ack_expected_list[0] is None: # Case no ACK
value = self._file.query(cmd, size)
else: # Case with ACKs
_ = self._file.query(cmd, size=0) # Send the cmd, don't read
for ack_expected in ack_expected_list: # Read and verify ACKs
ack = self.read()
if ack != ack_expected:
raise AcknowledgementError(
"Incorrect ACK message received: got {} "
"expected {}".format(ack, ack_expected))
value = self.read(size) # Now read in our return data
if self.prompt is not None:
prompt = self.read(len(self.prompt))
if prompt != self.prompt:
raise PromptError("Incorrect prompt message received: got {} "
"expected {}".format(prompt, self.prompt))
return value
def sendcmd(self, cmd):
"""
Sends a command without waiting for a response.
:param str cmd: String containing the command to
be sent.
"""
self._file.sendcmd(str(cmd))
ack_expected_list = self._ack_expected(cmd) # pylint: disable=assignment-from-none
if not isinstance(ack_expected_list, (list, tuple)):
ack_expected_list = [ack_expected_list]
for ack_expected in ack_expected_list:
if ack_expected is None:
break
ack = self.read()
if ack != ack_expected:
raise AcknowledgementError(
"Incorrect ACK message received: got {} "
"expected {}".format(ack, ack_expected)
)
if self.prompt is not None:
prompt = self.read(len(self.prompt))
if prompt != self.prompt:
raise PromptError(
"Incorrect prompt message received: got {} "
"expected {}".format(prompt, self.prompt)
)