The document nRF51422_Evaluation_Kit_User_Guide_v2.0.pdf says:
Locate the Heart Rate demo project found in the folder ARM\Device\Nordic\nrf51422\Board\pca10003\s310\ble_app_hrs\arm.
There is no such example after installing nrf51_sdk_v5_2_0_39364.msi or in the file nrf51_sdk_v6_0_0_43681.zip. Where can I find this example?
Meanwhile I tried the nRF6310 version of this example program and got it to compile and install by changing the board #define plus a few other changes, but it doesn't appear to run correctly (no blinking LED, no UART messages.)