Mitutoyo SJ-210 - Rc (JIS2001, ISO1997, ANSI, VDA, Free): Average Height; Pc (JIS1994, Free), Rpc (ANSI): Peak Count

No. 99MBB122A
18-24
18.5.10 Rc (JIS2001, ISO1997, ANSI, VDA, Free): Average height
Portions of the evaluation profile that project upwards are called “profile element
mountains”, and portions of the profile that project downwards are called “profile element
valleys”. A mountain followed by a valley is called a “profile element”. Rc is the arithmetic
mean of the height (Zt) of each profile element.
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n
i
Zti
n
Rc
1
1
 Depending on the calculation definition in the parameter-conditions settings, the
calculation method differs.
(2) Zt: Zt > Zmin (Example: Zmin = 10% of Rz)
Rc Average height
Zt > Zmin Mountains and valleys that do not meet the condition “Zmin = Rz for
slice-level height (% or µm)” are not considered profile elements and are excluded
from the calculation.
 When the value for Xs, shown in the previous graph, is less than 1% of the sampling
length, the section of the profile is not considered a profile element and is excluded
from the calculation.
18.5.11 Pc (JIS1994, Free), RPc (ANSI): Peak count
Pc is the reciprocal of the mean width of the mountains and valleys (SM).
Pc = Unit length/Sm (Unit length = 1 cm (0.4 in))
 For ANSI, Pc is defined over the evaluation length.
Zt
Xt3 Xt1 Xt2
Peak Peak
10% of Rz or more
Evaluation profiles
Mean line
Valley
Valley
Valley
Peak