Compare HRM-Pro with internal Epix 2 HR sensor

Azo said:

How can I compare HRM-Pro data with internal Epix 2 HR sensor?

Export the activity file in the default FIT file format, load it to FIT File Viewer, click Chart at the top, select "wrist heart rate" for Y1 and "external heart rate" for Y2

Thank you, it looks that the external HRM-Pro is just recorded and not used for activity evaluation. Under Stats in Activity details is shown the WHR graph and not the HRM-Pro graph. It means the HRM-Pro is useless. 

Is there a setting to force the watch to use the external HR for calculations? 

Sounds strange. The external HRM has always the priority, as long as it transmits credible data. However, if you disable the option "Source Switching" in the settings Sensors & Accessories » Wrist HR, or if you disable the wrist HR sensor (i.e. by activating the Jacket Power Mode in the activity profile), the watch will use only the external HRM.

This is the superimposed WHR and HRM. Next is the HR graph from the activity Stats. it is clearly the WHR.

In the Activity Stats is shown the WHR. And this is what is considered for Activity evaluation. 

Sounds indeed strange.

"Wrist heart rate" and "heart rate"are identical. External HR is clearly different.

Well, it looks like there are some tiny differences. Try zooming in, using the Filter function. The watch may be combining both sources, and for some (strange) reason, it trusts its own sensor more than the external one, but it is not 100% identical, hence it is clear both sources were somehow used.

Anyway, I recommend contacting the Support, sending them the screenshots, and asking for explanation why the watch prioritizes the wrist HR over clearly more credible external HRM strap.