IB Charts / QT Charts

Discussion in 'Trading Software' started by BSAM, Aug 23, 2007.

  1. BSAM


    Last couple of days I've been using IB charts. I am seeing very different data when compared to a QT chart.

    Here's what I'm not getting: My broker is IB. My charting software is QT. Why isn't a candle on a QT chart not exactly the same as a candle on an IB chart if I am getting my data from IB?

    As you know, this makes a difference on entry/exit decisions. Why do these discrepancies exist?

    I executed a trade today on a particular candle @ 26.27. It was executed on the bottom of the candle on the IB chart. QT shows this particular candle had a low of 26.26.

    The IB T&S data indicates that no trades took place below 26.27 on this particular candle.

    I realize the IB data does not show every tick, but again, since I fill my QT charts with IB data, why are the charts not identical?
  2. JackR


    If I recall correctly IB does not send the time with quotes. Time and Sales is different. That time is from the exchange server I believe.

    Because IB does not send the time IB charts build the bars based on an internal TWS "clock". QT also adds the time locally when it builds the bars. The two clocks are probably not perfectly synchronized.

    In QT - Open the "Options\Edit Preferences" Menu item and go to "Data Sources/ Proxy" Click the Quote tab. You'll probably see the "Always Use System Time for quotes" box checked. It doesn't really matter as QT automatically adds the time because IB does not. But it will affect other quotes from sources with time.

    Close the window. Next re-open the Options\Edit Preferences Menu and select "Timing". At the bottom of the window select "Sync Time". That will show you Naval Observatory Time and your computer's time. Note any difference.

    Next go to the TWS and see what time appears in the lower right corner of the main screen. Now open QT, drag the sync time window onto the TWS window so that you can see the TWS time and the QT Sync Time screen.

    If there is any difference that will explain your discrepancy. If there isn't then you've got me.

    Windows has some sort of auto clock update which you may have enabled. Double-click the timeand check the Internet Time tab - Windows XP. However, it does not run that often so your local clock may drift between resets. The two clocks may have been synched automatically recently and you would have been unaware of its happening.