HEIDENHAIN TNC 620 (73498x-01) ISO programming User Manual
Page 484

484
Comparison: Differences in Program Run, 
traverse movements
Caution: Check the traverse movements!
NC programs that were created on earlier TNC controls 
may lead to different traverse movements or error 
messages on a TNC 620!
Be sure to take the necessary care and caution when 
running-in programs!
Please find a list of known differences below. The list does 
not pretend to be complete!
Function
TNC 620
iTNC 530
Handwheel-superimposed traverse with 
M118
Effective in the active coordinate 
system (which may also be rotated or 
tilted), or in the machine-based 
coordinate system, depending on the 
setting in the 3-D ROT menu for manual 
operation
Effective in the machine-based 
coordinate system
M118 in conjunction with M128
Function not available
Function available
Approach/Departure with APPR/DEP, R0 is 
active, contour element plane is not 
equal to working plane
If possible, the blocks are executed in 
the defined contour element plane, 
error message for APPRLN, DEPLN, 
APPRCT
, DEPCT
If possible, the blocks are executed in 
the defined working plane; error 
message for APPRLN, APPRLT, APPRCT, 
APPRLCT
Scaling approach/departure movements 
(APPR/DEP/RND)
Axis-specific scaling factor is allowed, 
radius is not scaled
Error message
Approach/departure with APPR/DEP
Error message if R0 is programmed for 
APPR
/DEP LN or APPR/DEP CT
Tool radius 0 and compensation 
direction RR are assumed
Approach/departure with APPR/DEP if 
contour elements with length 0 are 
defined
Contour elements with length 0 are 
ignored. The approach/departure 
movements are calculated for the first or 
last valid contour element
An error message is issued if a contour 
element with length 0 is programmed 
after the APPR block (relative to the first 
contour point programmed in the APPR 
block)
For a contour element with length 0 
before a DEP block, the TNC does not 
issue an error message, but uses the 
last valid contour element to calculate 
the departure movement
Effect of Q parameters
Q60
to Q99 (or QS60 to QS99) are always
local
Q60
to Q99 (or QS60 to QS99) are local or
global, depending on MP7251 in 
converted cycle programs (.cyc). Nested 
calls may cause problems
