added data logging functionality

csv_logging.py

@@ -0,0 +1,99 @@
+# This file contains functions related to logging data from the program to a CSV file
+# They are mainly but not only called by the ConfigureLogging class in User_Interface.py
+
+import pandas as pd
+import globals as g
+from datetime import datetime
+import os
+from tkinter import filedialog
+from tkinter import messagebox
+import User_Interface as ui
+
+log_data = pd.DataFrame()  # pandas data frame containing logged data
+logging = False  # Bool to indicate if data should be logged at the moment
+unsaved_data = False  # Bool to indicate if there is unsaved data, set to True each time a datapoint is logged
+zero_time = datetime.now()
+
+# create dictionary with all value handles that could be logged
+# Key: String that is displayed in UI and column headers. Also serves as handle to access dictionary elements.
+# Keys are the same as the rows in the status display ToDo (optional): use this for the status display
+# Content: name of the corresponding attribute in the Axis class (in cage_func.py).
+# Important: attribute handle must match definition in Axis class exactly, used with axis.getattr() to get values.
+axis_data_dict = {
+    'PSU Status': 'connected',
+    'Voltage Setpoint': 'voltage_setpoint',
+    'Actual Voltage': 'voltage',
+    'Current Setpoint': 'current_setpoint',
+    'Actual Current': 'current',
+    'Target Field': 'target_field_comp',
+    'Trgt. Field Raw': 'target_field_comp',
+    'Target Current': 'target_current',
+    'Inverted': 'polarity_switched'
+}
+
+
+def triple_list(key_list):  # creates list with each entry of key_list tripled with axis names before it
+    new_list = []  # initialize list
+    for key in key_list:  # go through the given list
+        for axis_name in ['X', 'Y', 'Z']:  # per given list entry create three, one for each axis
+            new_list.append(' '.join((axis_name, key)))  # put axis_name before the given entry and append to new list
+    return new_list
+
+
+def init_log_dataframe(key_list):  # probably not needed, ToDo: remove
+    global log_data
+    columns = triple_list(key_list)
+    log_data = pd.DataFrame(columns=columns)
+
+
+def log_datapoint(key_list):  # ToDo: comments
+    global log_data
+    global unsaved_data
+    date = datetime.now().date()
+    time = datetime.now().strftime("%H:%M:%S,%f")
+    t = (datetime.now() - zero_time).total_seconds()
+    data = [[date, time, t]]
+    for key in key_list:
+        for axis in g.AXES:
+            data[0].append(getattr(axis, axis_data_dict[key]))  # get value
+    column_names = ["Date", "Time", "t (s)", *triple_list(key_list)]
+    new_row = pd.DataFrame(data, columns=column_names)
+    log_data = log_data.append(new_row, ignore_index=True)
+    unsaved_data = True
+
+
+def select_file():  # select a file to write logs to
+    directory = os.path.abspath(os.getcwd())  # get project directory
+    # open file selection dialogue and save path of selected file
+    filepath = filedialog.asksaveasfilename(initialdir=directory, title="Set log file",
+                                            filetypes=([("Comma Separated Values", "*.csv*")]),
+                                            defaultextension=[("Comma Separated Values", "*.csv*")])
+
+    if filepath == '':  # this happens when file selection window is closed without selecting a file
+        ui.ui_print("No file selected, can not save logged data.")
+        return None
+    else:  # a valid file name was entered
+        return filepath
+
+
+def write_to_file(dataframe, filepath):
+    # get global variables for use in this function:
+    global unsaved_data
+    if filepath is not None:  # user has selected a file and no errors occurred
+        ui.ui_print("Writing logged data to file", filepath)
+        try:
+            # write data collected in log_data DataFrame to csv file in german excel format:
+            dataframe.to_csv(filepath, index=False, sep=';', decimal=',')
+        except PermissionError:
+            message = "No permission to write to: \n%s. \nFile may be open in another program." % filepath
+            messagebox.showerror("Permission Error", message)
+        except BaseException as e:
+            message = "Error while trying to write to file \n%s.\n%s" % (filepath, e)
+            messagebox.showerror("Error!", message)
+        else:  # no exceptions occurred
+            unsaved_data = False  # data has been saved, so no unsaved data remains
+
+
+def clear_logged_data():  # clears all logged data from data frame
+    global log_data  # get global variable
+    log_data = pd.DataFrame()  # reset to an empty data frame, i.e. clear all logged data