Anyone have a PCF to show when the 8 EMA is crossing down the opening pice on the 10 min chart ?

There is no way to automatically determine the opening price of the trading day in an intraday Personal Criteria Formula. You would need to have a different formula each time a new 10 minute bar forms.

I was meaning the opening price of the day. The eight crossing down the opening price of the day.

I certainly could be wrong, but I am fairly sure I am understanding what you are asking.

During the opening bar of the trading day an intraday Condition Formula for the 8 period exponential crossing down through the open of the trading day could be written as follows.

XAVGC8 < O AND O <= XAVGC8.1

But during the second bar of the trading day an intraday Condition Formula for the 8 period exponential moving average crossing down through the open of the trading day would need to increment the bars ago parameter for the open by 1.

XAVGC8 < O1 AND O1 <= XAVGC8.1

This keeps happening as each new intraday bar forms. So during the third bar of the trading day, the new formula would be the following.

XAVGC8 < O2 AND O2 <= XAVGC8.1

It doesn't matter what intraday time frame is being used as long as the time frame of the Condition Formula is set to match the time frame of the chart.