title: Make error bar to a converted value
body: <p>Im trying to make errorbars to a already converted value. I have value in the dat file as uk gallons per minute and have now converted it into m^3/min.</p>
  
  <p>My problem is that i cannot get my error bars when i also convert the value. Initially i just bracket the converting and then the accuracy on 0.0025(0.25%) but no error bars appear..</p>
  
  <pre><code>set yrange [34:37.5]
  set xlabel "Time [min]"
  set ylabel "Flow [m^3/min]"
  plot '2015 08 30 0000 Pelletizer Feed (Wide).dat'  every ::2372::2459 using 4:($17*0.161) w l lc rgb 'green' title "Run 1", \
                          ''  every ::2372::2459 using 4:17:(($17*0.161)*0.0025) w errorbar lc rgb 'green' notitle, \
      '2015 08 30 0000 Pelletizer Feed (Wide).dat'  every ::2498::2565 using 4:($17*0.161) w l lc rgb 'blue' title "Run 2", \
                                  ''  every ::2498::2565 using 4:17:(($17*0.161)*0.0025) w errorbar lc rgb 'blue' notitle, \
                          35.42 title "SP" with lines linestyle 2
  </code></pre>