Siemens SINUMERIK 840D sl Function Manual

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15.9.6 Reference point approach with absolute encodersTraversing movement releaseIf for a mchine axis with adjusted absolute value encoder as active measuring system,reference point traversing is activated (manual in the mode JOG-REF or automatic accordingto part program instruction G74), the machine axis travels depending on the parameterizedrelease traversing movement.MD34330 $MA_REFP_STOP_AT_ABS_MARKER = Value Meaning0 Traversing is enabled.When reference point approach is initiated, the machine axis moves to the reference pointposition. Reference point approach is completed when the reference point position is reached.1 Traversing is not enabled.After the activation of the reference point travel, the machine axis does not travel and thereference point travel is immediately completed.15.9.7 Reference point approach in rotary absolute encoders with external zero markFunctionTo be able to use the reference point approach with a zero mark, as is usual in incrementalencoders (refer to Section "Referencing with incremental measurement systems(Page 1154)"), also with absolute encoders, the missing HW zero marks are created in softwareform once every encoder revolution, always at the same position within the rotation.Difference compared to referencing with incremental encodersAn absolute encoder with replacement zero mark should not be considerd as a completeequivalent of an incremental encoder. All the properties of the absolute encoder are retained.The following table lists the different properties of incremental and absolute encoders:Table 15-1 Properties of incremental and absolute encodersProperty Incremental encoder Absolute encoderEncoder type MD30240 $MA_ENC_TYPE= 1 = 4Internal encoder position MD30250 $MA_ACT_POS_ABSValue is updated only in MD34210 ≥ 1 Value is updated only in MD30270 = 0Traversing range extension MD30270 $MA_ENC_ABS_BUFFERINGNo effect = 0 (default): ActiveReference point offset MD34090 $MA_REFP_MOVE_DIST_CORRValue input allowed Value is updated exclusively via controlR1: Referencing15.9 Referencing with absolute encodersBasic Functions1186 Function Manual, 01/2015, 6FC5397-0BP40-5BA2