Siemens SINUMERIK 808D ADVANCED Programming And Operating Manual page 127

Explanation of the parameters
RFP and RTP (reference plane and retraction plane)
Normally, reference plane (RFP) and retraction plane (RTP) have different values. The cycle assumes that the retraction
plane precedes the reference plane. This means that the distance from the retraction plane to the final drilling depth is larger
than the distance from the reference plane to the final drilling depth.
SDIS (safety clearance)
The safety clearance (SDIS) acts with reference to the reference plane. This is brought forward by the safety clearance.
The direction in which the safety clearance is active is automatically determined by the cycle.
DP and DPR (final drilling depth)
The final drilling depth can be specified either absolute (DP) or relative (DPR) to the reference plane.
With relative specification, the cycle will calculate the resulting depth automatically using the positions of reference and
retraction planes.
Note
If a value is entered both for DP and for DPR, the final drilling depth is derived from DPR. If this differs from the absolute
depth programmed via DP, the message "Depth: Corresponding to value for relative depth" is output in the dialog line.
If the values for reference and retraction planes are identical, a relative depth specification is not permitted. The error
message 61101 "Reference plane defined incorrectly" is output and the cycle is not executed. This error message is also
output if the retraction plane is located after the reference plane, i.e. its distance to the final drilling depth is smaller.
Programming and Operating Manual (Milling)
127
6FC5398-4DP10-0BA1, 01/2014