Mercurial > pygpibtoolkit / file comparison
comparison: prologix.py
prologix.py
- changeset 13
- 78e3e839658b
- child 14
- 07e2cbf140df
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| 12:a04bea92c509 | 13:78e3e839658b |
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| 1 """ | |
| 2 Prologix | |
| 3 ======== | |
| 4 | |
| 5 Module defining a communication object to talk to Prologix USB-GPIB controler. | |
| 6 | |
| 7 """ | |
| 8 import serial | |
| 9 import time | |
| 10 | |
| 11 import gpib | |
| 12 from gpib import ConnectionError | |
| 13 | |
| 14 GPIB_CONTROLLER = 1 | |
| 15 GPIB_DEVICE = 0 | |
| 16 | |
| 17 class GPIB(object): | |
| 18 _retries = 15 | |
| 19 def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1, | |
| 20 address=0, mode=1): | |
| 21 """ | |
| 22 Create a new GPIB controller for the Prologix USB-GPIB device | |
| 23 located on serial device 'device'. | |
| 24 """ | |
| 25 self._cnx = serial.Serial(port=device, baudrate=baudrate, timeout=timeout) | |
| 26 self._timeout = timeout | |
| 27 | |
| 28 self.set_mode(mode) | |
| 29 self.set_address(address) | |
| 30 | |
| 31 def set_address(self, address): | |
| 32 """ | |
| 33 Set the address of the GPIB device: | |
| 34 | |
| 35 - if the device is the Controller In Charge, this is the | |
| 36 address of the device commands are sent to, | |
| 37 | |
| 38 - if the device is in GPIB_DEVICE mode, this is its address. | |
| 39 """ | |
| 40 self._set_cmd('addr', address) | |
| 41 self._adress = address | |
| 42 | |
| 43 def set_mode(self, mode): | |
| 44 """ | |
| 45 Set GPIB device mode to 'mode': | |
| 46 | |
| 47 - GPIB_CONTROLLER: set the device as the Controller In Charge | |
| 48 on the GPIB bus | |
| 49 | |
| 50 - GPIB_DEVICE: set the device as a standard GPIB device on the | |
| 51 bus. | |
| 52 """ | |
| 53 self._set_cmd('mode', mode) | |
| 54 self._mode = mode | |
| 55 | |
| 56 def set_controller(self): | |
| 57 """ | |
| 58 Set GPIB device the Controller In Charge on the GPIB bus. | |
| 59 """ | |
| 60 self.set_mode(1) | |
| 61 | |
| 62 def set_device(self): | |
| 63 """ | |
| 64 Set the GPIB device as a simple device on the GPIB bus. | |
| 65 """ | |
| 66 self.set_mode(0) | |
| 67 | |
| 68 def send_command(self, cmd): | |
| 69 """ | |
| 70 Send the specified GPIB command on the bus (must be the CIC), | |
| 71 and read the answer. | |
| 72 """ | |
| 73 assert self._mode == 1 | |
| 74 self._cnx.write(cmd+'\r') | |
| 75 time.sleep(self._timeout) # required? | |
| 76 ret = self._cnx.readlines() | |
| 77 return ''.join(ret) | |
| 78 | |
| 79 def check_srq(self): | |
| 80 """ | |
| 81 Check the SRQ line | |
| 82 """ | |
| 83 assert self._mode == 1, "must be the Controller In Charge" | |
| 84 self._cnx.write('++srq\r') | |
| 85 ret = self._cnx.readline().strip() | |
| 86 if ret: | |
| 87 return bool(int(ret)) | |
| 88 return None | |
| 89 | |
| 90 def poll(self): | |
| 91 """ | |
| 92 Poll every address, and return a dictionnary | |
| 93 {add: status, ...} | |
| 94 """ | |
| 95 assert self._mode == 1, "must be the Controller In Charge" | |
| 96 dico = {} | |
| 97 for add in range(31): | |
| 98 self._cnx.write('++spoll %d\r'%i) | |
| 99 ret = self._cnx.readline().strip() | |
| 100 if ret: | |
| 101 dico[i] = int(ret) | |
| 102 return dico | |
| 103 | |
| 104 def _read(self): | |
| 105 for i in range(self._retries): | |
| 106 rdata = self._cnx.readline() | |
| 107 if rdata.strip() != "": | |
| 108 break | |
| 109 time.sleep(self._timeout) | |
| 110 return rdata | |
| 111 | |
| 112 def _set_cmd(self, cmd, value): | |
| 113 self._cnx.write('++%s %d\r'%(cmd, value)) | |
| 114 self._cnx.write('++%s\r'%(cmd)) | |
| 115 rval = self._read().strip() | |
| 116 if not rval.isdigit() or int(rval) != value: | |
| 117 raise ConnectionError("Can't set GPIB %s to %s [ret=%s]"%(cmd, value, repr(rval))) |
