Mercurial > pygpibtoolkit / file comparison
comparison: gpib.py
gpib.py
- changeset 2
- cd9efa64f6da
- child 7
- 2e2742648546
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| 1:0670b1f5c155 | 2:cd9efa64f6da |
|---|---|
| 1 """ | |
| 2 gpib: create serial connection to GPIB-USB device (ProLogix is the | |
| 3 only supported device for now). | |
| 4 """ | |
| 5 import serial | |
| 6 from serial.serialutil import SerialException | |
| 7 import time | |
| 8 | |
| 9 class ConnectionError(Exception): | |
| 10 pass | |
| 11 | |
| 12 class GPIB(object): | |
| 13 _retries = 10 | |
| 14 def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1, | |
| 15 address=0, mode=1): | |
| 16 self._cnx = serial.Serial(port=device, baudrate=baudrate, timeout=timeout) | |
| 17 self._timeout = timeout | |
| 18 | |
| 19 self.set_mode(mode) | |
| 20 if mode == 1: | |
| 21 self.set_address(address) | |
| 22 | |
| 23 def _set_cmd(self, cmd, value): | |
| 24 self._cnx.write('++%s %d\r'%(cmd, value)) | |
| 25 rval = self._read() | |
| 26 if not rval.isdigit() or int(rval) != value: | |
| 27 raise ConnectionError("Can't set GPIB %s to %s"%(cmd, value)) | |
| 28 | |
| 29 def set_address(self, address): | |
| 30 self._set_cmd('addr', address) | |
| 31 self._adress = address | |
| 32 | |
| 33 def set_mode(self, mode): | |
| 34 self._set_cmd('mode', mode) | |
| 35 self._mode = mode | |
| 36 | |
| 37 def _read(self): | |
| 38 for i in range(self._retries): | |
| 39 rdata = self._cnx.readline() | |
| 40 if rdata.strip() != "": | |
| 41 break | |
| 42 time.sleep(self._timeout) | |
| 43 return rdata |
