Question

我正试图在x86_64 linux机器（CentOS 7）上通过python控制Keithley 2410。我正在使用python 2.7.5，NI-VISA 16和PyVISA 1.8。吉时利通过RS232到USB电缆连接到计算机，它配置为RS232通信（参数：波特57600，位8，奇偶校验无，终结器，流量控制器无）。当我尝试查询Keithley时，我收到超时错误，如下所示：

>>> import visa
>>> rm = visa.ResourceManager()
>>> print(rm.list_resources())
(u'ASRL1::INSTR', u'ASRL2::INSTR')
>>> keithley = rm.open_resource("ASRL2::INSTR")
>>> print(keithley.query('*IDN?'))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/site-packages/pyvisa/resources/messagebased.py", line 407, in query
return self.read()
File "/usr/lib/python2.7/site-packages/pyvisa/resources/messagebased.py", line 332, in read
message = self.read_raw().decode(enco)
File "/usr/lib/python2.7/site-packages/pyvisa/resources/messagebased.py", line 306, in read_raw
chunk, status = self.visalib.read(self.session, size)
File "/usr/lib/python2.7/site-packages/pyvisa/ctwrapper/functions.py", line 1582, in read
ret = library.viRead(session, buffer, count, byref(return_count))
File "/usr/lib/python2.7/site-packages/pyvisa/ctwrapper/highlevel.py", line 188, in _return_handler
raise errors.VisaIOError(ret_value)
pyvisa.errors.VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.

Answer 1

PyVISA 1.8应默认为串行的'\ r'行终止，因此您的2410可能无法接收启动解析命令所需的'\ n'。 Try doing

keithley.write_termination = '\n'
keithley.read_termination = '\n'

在open_resource()电话之后

。

Answer 2

感谢您的建议，但似乎我需要明确设置波特率。

rm = visa.ResourceManager()
smu = rm.open_resource("ASRL2::INSTR")
smu.baud_rate = 57600

Keithley 2410和PyVISA - VI_ERROR_TMO：超时在操作完成之前到期

2 个答案: