o<p_tool> sub
F#<_ini[TOOLSENSOR]RAPID_FEED>
G90 G53 G1 Z[#<_ini[AXIS_Z]MAX_LIMIT>]
G53 G1 X[#<_ini[TOOLSENSOR]X_PROBE_COORD>] Y[#<_ini[TOOLSENSOR]Y_PROBE_COORD>]
G53 G1 Z[#<_ini[TOOLSENSOR]Z_START>]
G4 P0.5
G91
F #<_ini[TOOLSENSOR]SEARCH_FEED>
G49
G38.2 Z #<_ini[TOOLSENSOR]Z_MAXPROBE>
#<zworkoffset> = [#[5203 + #5220 * 20] + #5213 * #5210]
G10 L1 P#5400 Z#<zworkoffset> (set new tool offset)
G43
G90 G53 G1 Z[#<_ini[TOOLSENSOR]Z_START>] F#<_ini[TOOLSENSOR]RAPID_FEED>
o<p_tool> endsub
M2

Say we are in G55 then #5220 would equal 2. (20 * 2) = 40. (5203 + 40) = 5243 which would be the Z location in G55.

5241-5250 - Coordinate System 2, G55 for X, Y, Z, A, B, C, U, V, W & R. Persistent.

probe_cal_round_boss.ngc: #<workspace_z> = #[5203 + [20 * #5220]]

( INI SECTION PARAMETERS )
( [TOOLSENSOR] )
( RAPID_FEED = 30 )
( SEARCH_FEED = 15 )
( PROBE_LEVEL_FEED = 5 )
( X_PROBE_COORD = 1 )
( Y_PROBE_COORD = 1 )
( Z_START = -.1 )
( Z_MAXPROBE = -2 )

in the linuxcnc documentation this example of gcode is provided
G49
G38.2 Z-100 F100
#<zworkoffset> = [#[5203 + #5220 * 20] + #5213 * #5210]
G10 L1 P#5400 Z#<zworkoffset> (set new tool offset)
G43
i want to understand this equation #<zworkoffset> = [#[5203 + #5220 * 20] + #5213 * #5210].
any help is appreciated

#[5203 + #5220 * 20] This is the value of the z offset of the currently active work offset system
Note: the offset value registers of all the work offset systems [1..9] are 20 registers apart.


+ #5213 * #5210] This adds the z offset of 52/G92 if it is applied, if it is not applied the product is equal to zero