## GrabData.py
## Gets all the data from the screen and then saves it as csv file
## Make sure all 4 Channels of the VNA are on Log Magnitude + Phase
## The CSV file will have 9 columns - frequency then 4x mag + phase

import visa
import os

def grabData(fname):

	print("Please wait, retrieving data...")
	## Get the VNA data
	VNA = visa.instrument("GPIB::06")

	VNA.write("CH1")
	f = VNA.ask_for_values("OFV")
	S11 = VNA.ask_for_values("OFD")

	VNA.write("CH2")
	S21 = VNA.ask_for_values("OFD")

	VNA.write("CH3")
	S12 = VNA.ask_for_values("OFD")

	VNA.write("CH4")
	S22 = VNA.ask_for_values("OFD")

	## Open the file to save data to
	file = open(fname,"w")

	## Write a header, to set up each channel
	file.write("Frequency,S11 Magnitude,S11 Phase,S21 Magnitude,S21 Phase,S12 Magnitude,S12 Phase,S22 Magnitude,S22 Phase \n")
	file.write("GHz,dB,deg,dB,deg,dB,deg,dB,deg \n")
	file.write("\n")

	## Loop through all the data, writing it line by line to a csv 	
	for m in range(len(f)-1):
		file.write(str(f[m+1]/1000000000) + ", " + str(S11[2*m+1]) + ", " + str(S11[2*m+2])+ ", " + str(S21[2*m+1]) + ", " + str(S21[2*m+2])+ ", " + str(S12[2*m+1])+ ", " + str(S12[2*m+2]) + ", " + str(S22[2*m+1])+ ", " +str(S22[2*m+2]) + "\n")

	file.close()
	VNA.close()

#end of grabData def

## Ask for the filename
t=raw_input("Enter name for file and then press RETURN: ")

## Open up a file and start writing
os.mkdir(t)

## Get the VNA data
VNA = visa.instrument("GPIB::06")

VNA.write("CH1")
refS11t = VNA.ask_for_values("RDT?")

VNA.write("CH2")
refS21t = VNA.ask_for_values("RDT?")

VNA.write("CH3")
refS12t = VNA.ask_for_values("RDT?")

VNA.write("CH4")
refS22t = VNA.ask_for_values("RDT?")


## Open file for extra information
fname = t + "/" + t + ".txt"
file = open(fname,"w")

file.write("Reference Delay - Time (s) \n")
file.write("S11: " + str(refS11t) + " \n")
file.write("S21: " + str(refS21t) + " \n")
file.write("S12: " + str(refS12t) + " \n")
file.write("S22: " + str(refS22t) + " \n")

file.close()

## take the measurement
fname = t + "/" + t + "_1_1.csv"
grabData(fname)