Peak count parameter Rpc is the number of profile elements (see Rsm) per cm.
In accordance with DIN EN ISO 21920, the following applies:
Rpc = 10 mm / Rsm
In accordance with DIN EN 10049 and ASME B46.1, the profile elements that exceed the upper set level of intersection c1 (generally 0.5 μm) and then fall below the lower level of intersection c2 (generally -0.5 μm) are counted.
In addition to the peak count parameter Rpc, the parameter HSC (high spot count) is occasionally used. HSC is the number of profile peaks per cm that exceed the set level of intersection c1.