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Entry type: FAQ Entry ID: 17823535, Entry date: 10/14/2004

Rotary axes with rotating distance-coded measuring system.

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What has to be taken into account when parameterizing rotating distance-coded measuring systems?


  • The distance of the equidistant reference marks must be entered into MD 34300 in degrees. This corresponds to the "basic distance" in accordance with the Heidenhain Catalog (generally for 1000 pulses).
  • The difference between two changing reference marks must be entered in degrees in MD 34310.

Example for ROD 780 C:
36000 pulses, basic distance 1000 pulses each 36 equidistant reference marks each 360/36=10degrees ---each MD34300=10
Difference between 2 changing reference marks = 1 pulse --each 10degrees/1000pulses*1pulse = 0.01degrees ---each MD34310=0,01

  • For limited rotary axes, problems are frequently encountered!!!
    Referencing does not function correctly if the traversing range can assume negative values and attempts to reference to these.

Traversing range -150degrees up to +150degrees
if the axis is located in the negative range and referencing is carried-out, a value is obtained shifted through 360degrees.
e.g. instead of -60degrees, 300degrees Remedy:
Set MD30340 (MODULO_RANGE_START) = -150 and
MD30310 (ROT_IS_MODULO) = 1.

The signal DB3x.DBX12.4 must be set  = 1 to activate the software end switches.

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