Siemens SINUMERIK 840D sl Programming Manual page 213

If $P_IFRAME, $P_BFRAME or $P_PFRAME are changed, $P_ACTFRAME is recalculated.
$P_ACTFRAME corresponds to $P_BFRAME:$P_IFRAME:$P_PFRAME
Basic frame and settable frame are effective after Reset if MD 20110 RESET_MODE_MASK
is set as follows:
Bit0=1, bit14=1 --> $P_UBFR (basic frame) acts
Bit0=1, bit5=1 --> $P_UIFR [$P_UIFRNUM](settable frame) acts
Predefined settable frames $P_UBFR
The basic frame is programmed with $P_UBFR, but it is not simultaneously active in the
parts program. The basic frame programmed with $P_UBFR is included in the calculation if
• Reset was activated and bits 0 and 14 are set in MD RESET_MODE_MASK and
• the statements G500,G54...G599 were executed.
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
6.1 Coordinate transformation via frame variables
Frames
6-7