unable to communicate with device

[gadamc]

From @palnitishh

---

hi, I am trying to communicate to the COM4 in my case using
pulser = qcsapphire.Pulser('COM4')

but end up with error

IndexError Traceback (most recent call last)
~\AppData\Local\Temp\ipykernel_8180\1879743324.py in
----> 1 pulser = qcsapphire.Pulser('COM4')

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in init(self, port, timeout)
88 self.open()
89 self._command_history = collections.deque(maxlen=1000)
---> 90 self._read_hardware_versions()
91
92 ## PRIVATE

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in _read_hardware_versions(self)
175
176 def _read_hardware_versions(self):
--> 177 res_str = self.query('*IDN?')
178 _, model_number, serial_number, firm_fpga = res_str.split(',')
179 self.model_number = model_number

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in query(self, data)
223 return_val = self._readlines()
224 else:
--> 225 return_val = self._readline()
226
227 return return_val

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in _readline(self)
162 '''
163 rdata = self._inst.readline()
--> 164 return self._check_error(rdata.decode('utf-8').strip())
165
166 def _readlines(self):

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in _check_error(self, string)
128 except Exception as e:
129 self._readlines() #flush out the read return on error to be ready for next query
--> 130 raise e
131
132 return string

~\AppData\Roaming\Python\Python39\site-packages\qcsapphire\pulser.py in _check_error(self, string)
107
108 try:
--> 109 if string[0] == '?':
110 if string[1] == '1':
111 raise Exception(f'Incorrect prefix, i.e. no colon or * to start command. Last write command == {self.last_write_command}')

IndexError: string index out of range

what do you think, am I mising some prequisites or something else is wrong?

[gadamc]

Hi @palnitishh. What is the output of

import qcsapphire
qcsapphire.discover_devices()

Actually, @palnitishh -- can you move this to a new issue?

And can you tell me details of the device you're using? Based on the error message, It looks like the *IDN command didn't work and the returned value from the device is an empty string.

[gadamc]

From @palnitishh

Hi @gadamc
thank you for your reply here is the screenshot.
COM4 is connected to Quantum Composer.

[gadamc]

From @palnitishh

the QC terminal is able to do *IDN command

[gadamc]

@palnitishh -- I'm not 100% sure, but the output from the QC terminal seems to suggest that your device is QC 9528. https://www.quantumcomposers.com/pulse-delay-generator-9520. This python package (qt3uw/qcsapphire) was only ever tested with QC 9200 devices. A quick review of the manual for the 9520 and the 9200 reveals some differences in USB communication. The 9520 uses USB 1 specs and the 9200 uses USB 2 specs. Relatedly, they use different default BAUD rates.
If you manage to find a way to update this package to support the 9520, let me know and perhaps a PR makes sense if it's not too much of a change and there don't seem to be any side effects.