writes a voltage measurement with second timestamp every second

fluke-8842a-logging.py

# Python script for voltage logging
import os.path
import sys
import Gpib
import time

# GPIB Address = 24
inst = Gpib.Gpib(0,24, timeout=60) 
inst.clear()  
inst.write("G8")
print(inst.read())

# VDC
inst.write("F1")

# 20V range
inst.write("R3")

# slow rate
inst.write("S0")

# external trigger by GPIB command "?" for measurment
inst.write("S0")

# logging loop
LogFile= 'fluke.csv'
with open(LogFile, 'w') as MeterLog:
  MeterLog.write('Timestamp,Voltage\n')
inst.write("?")
starttime = 0
while True:
  # file is closed while waiting, so that it can be loaded from the webserver
  with open(LogFile, 'a') as MeterLog:
    volt = float(inst.read())
    inst.write("?")
    t = time.time()
    if starttime == 0:
        starttime = t
        currenttime = starttime
    line = "%s,%f" % (t - starttime, volt)
    MeterLog.write(line + '\n')
    print(line)
  currenttime = currenttime + 1
  d = currenttime - time.time()
  if d > 0:
    time.sleep(d)