Mercurial > pygpibtoolkit / file comparison
comparison: gpib.py
gpib.py
- changeset 9
- 3b50c46fca56
- parent 7
- 2e2742648546
- child 12
- a04bea92c509
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| 8:aa3d55f78563 | 9:3b50c46fca56 |
|---|---|
| 7 import time | 7 import time |
| 8 | 8 |
| 9 class ConnectionError(Exception): | 9 class ConnectionError(Exception): |
| 10 pass | 10 pass |
| 11 | 11 |
| 12 GPIB_CONTROLLER = 1 | |
| 13 GPIB_DEVICE = 0 | |
| 14 | |
| 15 # IEEE 488.2 Status Byte constants | |
| 16 MAV = 0x10 # Message AVailable: bit 4 of the Status Byte | |
| 17 ESB = 0x20 # Event Status Bit: bit 5 of the Status Byte | |
| 18 MSS = 0x40 # Master Summary Status bit: bit 6 of the Status Byte (NOT | |
| 19 # sent in response to a serial poll) | |
| 20 RQS = 0x40 # Request Service: bit 6 of the Status Byte (when sent in | |
| 21 # response to a serial poll) | |
| 22 | |
| 23 # SESR constants (Standard Event Status Register) | |
| 24 PON = 0x80 # Power On: Power has been turned On since last register | |
| 25 # read access | |
| 26 URQ = 0x40 # User Request: the user has activated some device control | |
| 27 # (whatever the Remote Local state is) | |
| 28 CME = 0x20 # Command Error | |
| 29 EXE = 0x10 # Execution Error | |
| 30 DDE = 0x08 # Device Dependant Error | |
| 31 QYE = 0x04 # QuerY Error (attempt to read data while Output Queue is | |
| 32 # empty, or data in the OQ was lost) | |
| 33 RQC = 0x02 # Request Control: tell the CiC that the device wants to | |
| 34 # become the CiC | |
| 35 OPC = 0x01 # Operation Complete: device has completed any pending | |
| 36 # operation (ready to accept new commands). This bit is | |
| 37 # generated in response to a OPC command. | |
| 38 | |
| 39 ##################### | |
| 40 # HP3562A constants | |
| 41 | |
| 42 # GPIB buffer size is 3x80 characters lines | |
| 43 | |
| 44 # HP3562A Status Byte | |
| 45 RQS = 0x40 # Request Service: when sent in response to a serial poll | |
| 46 ERR = 0x20 # ERRor: GPIB error | |
| 47 RDY = 0x10 #ReaDY: ready to accept GPIB commands | |
| 48 | |
| 49 | |
| 12 class GPIB(object): | 50 class GPIB(object): |
| 13 _retries = 15 | 51 _retries = 15 |
| 14 def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1, | 52 def __init__(self, device="/dev/ttyUSB0", baudrate=115200, timeout=0.1, |
| 15 address=0, mode=1): | 53 address=0, mode=1): |
| 54 """ | |
| 55 Create a new GPIB controller for the Prologix USB-GPIB device | |
| 56 located on serial device 'device'. | |
| 57 """ | |
| 16 self._cnx = serial.Serial(port=device, baudrate=baudrate, timeout=timeout) | 58 self._cnx = serial.Serial(port=device, baudrate=baudrate, timeout=timeout) |
| 17 self._timeout = timeout | 59 self._timeout = timeout |
| 18 | 60 |
| 19 self.set_mode(mode) | 61 self.set_mode(mode) |
| 20 self.set_address(address) | 62 self.set_address(address) |
| 63 | |
| 64 def set_address(self, address): | |
| 65 """ | |
| 66 Set the address of the GPIB device: | |
| 67 | |
| 68 - if the device is the Controller In Charge, this is the | |
| 69 address of the device commands are sent to, | |
| 70 | |
| 71 - if the device is in GPIB_DEVICE mode, this is its address. | |
| 72 """ | |
| 73 self._set_cmd('addr', address) | |
| 74 self._adress = address | |
| 75 | |
| 76 def set_mode(self, mode): | |
| 77 """ | |
| 78 Set GPIB device mode to 'mode': | |
| 79 | |
| 80 - GPIB_CONTROLLER: set the device as the Controller In Charge | |
| 81 on the GPIB bus | |
| 82 | |
| 83 - GPIB_DEVICE: set the device as a standard GPIB device on the | |
| 84 bus. | |
| 85 """ | |
| 86 self._set_cmd('mode', mode) | |
| 87 self._mode = mode | |
| 88 | |
| 89 def set_controler(self): | |
| 90 """ | |
| 91 Set GPIB device the Controller In Charge on the GPIB bus. | |
| 92 """ | |
| 93 self.set_mode(1) | |
| 94 | |
| 95 def set_device(self): | |
| 96 """ | |
| 97 Set the GPIB device as a simple device on the GPIB bus. | |
| 98 """ | |
| 99 self.set_mode(0) | |
| 100 | |
| 101 def send_command(self, cmd): | |
| 102 """ | |
| 103 Send the specified GPIB command on the bus (must be the CIC), | |
| 104 and read the answer. | |
| 105 """ | |
| 106 assert self._mode == 1 | |
| 107 self._cnx.write(cmd+'\r') | |
| 108 time.sleep(self._timeout) # required? | |
| 109 ret = self._cnx.readlines() | |
| 110 return ''.join(ret) | |
| 111 | |
| 112 def check_srq(self): | |
| 113 """ | |
| 114 Check the SRQ line | |
| 115 """ | |
| 116 assert self._mode == 1, "must be the Controller In Charge" | |
| 117 self._cnx.write('++srq\r') | |
| 118 ret = self._cnx.readline().strip() | |
| 119 if ret: | |
| 120 return bool(int(ret)) | |
| 121 return None | |
| 122 | |
| 123 def poll(self): | |
| 124 """ | |
| 125 Poll every address, and return a dictionnary | |
| 126 {add: status, ...} | |
| 127 """ | |
| 128 assert self._mode == 1, "must be the Controller In Charge" | |
| 129 dico = {} | |
| 130 for add in range(31): | |
| 131 self._cnx.write('++spoll %d\r'%i) | |
| 132 ret = self._cnx.readline().strip() | |
| 133 if ret: | |
| 134 dico[i] = int(ret) | |
| 135 return dico | |
| 136 | |
| 137 def _read(self): | |
| 138 for i in range(self._retries): | |
| 139 rdata = self._cnx.readline() | |
| 140 if rdata.strip() != "": | |
| 141 break | |
| 142 time.sleep(self._timeout) | |
| 143 return rdata | |
| 21 | 144 |
| 22 def _set_cmd(self, cmd, value): | 145 def _set_cmd(self, cmd, value): |
| 23 self._cnx.write('++%s %d\r'%(cmd, value)) | 146 self._cnx.write('++%s %d\r'%(cmd, value)) |
| 24 self._cnx.write('++%s\r'%(cmd)) | 147 self._cnx.write('++%s\r'%(cmd)) |
| 25 rval = self._read().strip() | 148 rval = self._read().strip() |
| 26 if not rval.isdigit() or int(rval) != value: | 149 if not rval.isdigit() or int(rval) != value: |
| 27 raise ConnectionError("Can't set GPIB %s to %s [ret=%s]"%(cmd, value, repr(rval))) | 150 raise ConnectionError("Can't set GPIB %s to %s [ret=%s]"%(cmd, value, repr(rval))) |
| 28 | 151 |
| 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 |
