Siemens SINUMERIK 808D ADVANCED Programming And Operating Manual page 141

The cycle creates the following sequence of motions:
● Approach of the reference plane brought forward by the safety clearance by using G0
● Tapping to the final drilling depth
● Dwell time at thread depth (parameter DTB)
● Retraction to the reference plane brought forward by the safety clearance
● Retraction to the retraction plane with G0
Explanation of the parameters
For the parameters RTP, RFP, SDIS, DP, DPR, refer to Section "Drilling, centering - CYCLE81 (Page 126)".
DTB (dwell time)
The dwell time must be programmed in seconds.
SDR (direction of rotation for retraction)
SDR=0 must be set if the spindle direction is to reverse automatically.
If the machine data is defined such that no encoder is set (in this case, machine data MD30200 $MA_NUM_ENCS is 0), the
parameter must be assigned the value 3 or 4 for the direction of rotation; otherwise, alarm 61202 "No spindle direction
programmed" is output and the cycle is aborted.
SDAC (direction of rotation)
Because the cycle can also be called modally (see Section "Graphical cycle support in the program editor (Page 124)"), it
requires a direction of rotation for tapping further threaded holes. This is programmed in parameter SDAC and corresponds
to the direction of rotation programmed before the first call in the higher-level program. If SDR=0, the value assigned to
SDAC has no meaning in the cycle and can be omitted in the parameterization.
ENC (tapping)
If tapping is to be performed without encoder although an encoder exists, parameter ENC must be assigned value 1.
If, however, no encoder is installed and the parameter is assigned the value 0, it is ignored in the cycle.
MPIT and PIT (thread lead as a thread size and as a value)
The parameter for the lead is only relevant if tapping is performed with encoder. The cycle calculates the feedrate from the
spindle speed and the lead.
The value for the thread lead can be defined either as the thread size (for metric threads between M3 and M48 only) or as a
value (distance from one thread turn to the next as a numerical value). Any parameters not required are omitted in the call or
assigned the value zero.
If the two lead parameters have conflicting values, alarm 61001 "Thread lead wrong" is generated by the cycle and cycle
execution is aborted.
Programming and Operating Manual (Milling)
141
6FC5398-4DP10-0BA1, 01/2014