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This shows you the differences between two versions of the page.

--- en:python-ivi:writing-drivers [2013/07/22 04:39]
alex
+++ en:python-ivi:writing-drivers [2013/07/22 06:17] (current)
alex
@@ Line 1: / Line 1: @@
-====== Writing New Python-IVI Drivers ======
+====== Writing New Python IVI Drivers ======
 Note: this page is under construction
@@ Line 17: / Line 17: @@
 Test the interface and identity query by instantiating your driver and connecting to the instrument by running something like this in ipython:
-<code>
+<code python>
 import ivi
 mso = ivi.agilent.agilentMSO7104A("TCPIP0::192.168.1.104::INSTR")
@@ Line 28: / Line 28: @@
 Finally, you need to go write python code for all of the functions that the instrument supports. Take a look at some ''_get''/''_set'' pairs for some of the existing drivers to see the format. It's rather straightforward but quite tedious.
+===== Driver Template =====
+This is a sample template driver that incorporates all of the major components.  It is drawn from the Agilent 7000 series driver.
+<code python>
+"""
+Python Interchangeable Virtual Instrument Library
+Copyright (c) 2012 Alex Forencich
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+import struct
+from .. import ivi
+from .. import scope
+AcquisitionTypeMapping = {
+        'normal': 'norm',
+        'peak_detect': 'peak',
+        'high_resolution': 'hres',
+        'average': 'aver'}
+# more instrument-specific sets and mappings
+class agilent7000(ivi.Driver, scope.Base, scope.TVTrigger,
+                scope.GlitchTrigger, scope.WidthTrigger, scope.AcLineTrigger,
+                scope.WaveformMeasurement, scope.MinMaxWaveform,
+                scope.ContinuousAcquisition, scope.AverageAcquisition,
+                scope.SampleMode, scope.AutoSetup):
+    "Agilent InfiniiVision 7000 series IVI oscilloscope driver"
+    def __init__(self, *args, **kwargs):
+        self._analog_channel_name = list()
+        self._analog_channel_count = 4
+        self._digital_channel_name = list()
+        self._digital_channel_count = 16
+        self._channel_label = list()
+        # other per-channel instrument-specific variables that are
+        # referenced in _init_channels
+        super(agilent7000, self).__init__(*args, **kwargs)
+        self._instrument_id = 'AGILENT TECHNOLOGIES'
+        self._analog_channel_name = list()
+        self._analog_channel_count = 4
+        self._digital_channel_name = list()
+        self._digital_channel_count = 16
+        self._channel_count = 20
+        self._bandwidth = 1e9
+        # initialize other instrument-specific variables
+        self._identity_description = "Agilent InfiniiVision 7000 series IVI oscilloscope driver"
+        self._identity_identifier = ""
+        self._identity_revision = ""
+        self._identity_vendor = ""
+        self._identity_instrument_manufacturer = "Agilent Technologies"
+        self._identity_instrument_model = ""
+        self._identity_instrument_firmware_revision = ""
+        self._identity_specification_major_version = 4
+        self._identity_specification_minor_version = 1
+        self._identity_supported_instrument_models =['DSO7012A','DSO7014A','DSO7032A',
+                'DSO7034A','DSO7052A','DSO7054A','DSO7104A','MSO7012A','MSO7014A','MSO7032A',
+                'MSO7034A','MSO7052A','MSO7054A','MSO7104A','DSO7012B','DSO7014B','DSO7032B',
+                'DSO7034B','DSO7052B','DSO7054B','DSO7104B','MSO7012B','MSO7014B','MSO7032B',
+                'MSO7034B','MSO7052B','MSO7054B','MSO7104B']
+        self.channels._add_property('label',
+                        self._get_channel_label,
+                        self._set_channel_label)
+        # other instrument specific properties
+        self._init_channels()
+    def initialize(self, resource = None, id_query = False, reset = False, **keywargs):
+        "Opens an I/O session to the instrument."
+        self._channel_count = self._analog_channel_count + self._digital_channel_count
+        super(agilent7000, self).initialize(resource, id_query, reset, **keywargs)
+        # interface clear
+        if not self._driver_operation_simulate:
+            self._clear()
+        # check ID
+        if id_query and not self._driver_operation_simulate:
+            id = self.identity.instrument_model
+            id_check = self._instrument_id
+            id_short = id[:len(id_check)]
+            if id_short != id_check:
+                raise Exception("Instrument ID mismatch, expecting %s, got %s", id_check, id_short)
+        # reset
+        if reset:
+            self.utility.reset()
+    def _load_id_string(self):
+        if self._driver_operation_simulate:
+            self._identity_instrument_manufacturer = "Not available while simulating"
+            self._identity_instrument_model = "Not available while simulating"
+            self._identity_instrument_firmware_revision = "Not available while simulating"
+        else:
+            lst = self._ask("*IDN?").split(",")
+            self._identity_instrument_manufacturer = lst[0]
+            self._identity_instrument_model = lst[1]
+            self._identity_instrument_firmware_revision = lst[3]
+            self._set_cache_valid(True, 'identity_instrument_manufacturer')
+            self._set_cache_valid(True, 'identity_instrument_model')
+            self._set_cache_valid(True, 'identity_instrument_firmware_revision')
+    def _get_identity_instrument_manufacturer(self):
+        if self._get_cache_valid():
+            return self._identity_instrument_manufacturer
+        self._load_id_string()
+        return self._identity_instrument_manufacturer
+    def _get_identity_instrument_model(self):
+        if self._get_cache_valid():
+            return self._identity_instrument_model
+        self._load_id_string()
+        return self._identity_instrument_model
+    def _get_identity_instrument_firmware_revision(self):
+        if self._get_cache_valid():
+            return self._identity_instrument_firmware_revision
+        self._load_id_string()
+        return self._identity_instrument_firmware_revision
+    def _utility_disable(self):
+        pass
+    def _utility_error_query(self):
+        error_code = 0
+        error_message = "No error"
+        if not self._driver_operation_simulate:
+            error_code, error_message = self._ask(":system:error?").split(',')
+            error_code = int(error_code)
+            error_message = error_message.strip(' "')
+        return (error_code, error_message)
+    def _utility_lock_object(self):
+        pass
+    def _utility_reset(self):
+        if not self._driver_operation_simulate:
+            self._write("*RST")
+            self.driver_operation.invalidate_all_attributes()
+    def _utility_reset_with_defaults(self):
+        self._utility_reset()
+    def _utility_self_test(self):
+        code = 0
+        message = "Self test passed"
+        if not self._driver_operation_simulate:
+            code = int(self._ask("*TST?"))
+            if code != 0:
+                message = "Self test failed"
+        return (code, message)
+    def _utility_unlock_object(self):
+        pass
+    def _init_channels(self):
+        super(agilent7000, self)._init_channels()
+        self._channel_name = list()
+        self._channel_label = list()
+        # init per-channel instrument-specific variables
+        for i in range(self._channel_count):
+            self._channel_name.append("channel%d" % (i+1))
+            self._channel_label.append("%d" % (i+1))
+            # init per-channel instrument-specific variables
+        self.channels._set_list(self._channel_name)
+    def _get_acquisition_start_time(self):
+        pos = 0
+        if not self._driver_operation_simulate and not self._get_cache_valid():
+            pos = float(self._ask(":timebase:position?"))
+            self._set_cache_valid()
+        self._acquisition_start_time = pos - self._get_acquisition_time_per_record() * 5 / 10
+        return self._acquisition_start_time
+    def _set_acquisition_start_time(self, value):
+        value = float(value)
+        value = value + self._get_acquisition_time_per_record() * 5 / 10
+        if not self._driver_operation_simulate:
+            self._write(":timebase:position %e" % value)
+        self._acquisition_start_time = value
+        self._set_cache_valid()
+    # more definitions
+</code>