Open up an MACD and you'll notice 3 numbers. The 1st and 2nd numbers are two moving averages. Usually it is 12-26. So the MACD measures the price difference between the 12 period EMA and the 26 period EMA and plots it on a graph as a lower study. If you change the firs number from 12 to 1, you will have a moving average that is averaging the last 1 period of time which means it will be the exact price. Then change the 2nd number to 200. Finally, if you don't want the trigger line to show, change that to 1 as well. So your MACD parameters are (1,200,1). Now you have an oscillator that measures the difference between the current price and the 200 day EMA.