Lenze 931W - Manual (Page 69)

Software implementation and parameter setting
Reference menu
Reference type
5

69 HB 13.0001-EN 3.0
The different possibilities resulting therefrom are demonstrated by 2 examples, which can
begatheredfromthe followingillustration. Theexamples referto alinear motion,defining
the ”positive direction” on the right side. In both cases, referencing is carried out to the
right limit switch (”Active high”).
Reference type ”Limit switch, right”, positive
reference speed
Reference type ”Limit switch, right”, negative
reference speed




 






Example 1 Example 2
 Limit switch signal level  V
reference
 Position  Edge
 Starting point  Limit switch
Fig. 7 Reference run to a limit switch
Example 1: A positive reference speed is to be set. The drive is traversed until the edge of
the limit switch is recognised. If the limit switch is entered, homing is carried out on this
edge.
Example 2: A negative reference speed is to be set. In this case, the drive decelerates its
speed to standstill when entering the limit switch and afterwards accelerates in the oppo-
site direction. Homing is carried out on the falling edge of the limit switch, which sets itself
when the limit switch is left.
End stop, left/right
Apart from referencing to a reference signal it is possible to select a mechanical limit stop
as a home position. In this connection, a mechanical limit stop is recognised in an
inverter-internal manner by means of the evaluation of the actual speed value and the
reference torque. If, in spite of the available reference torque no change in position is
effected for a period of 0.5 s (actual speed ~ 0), the mechanical limit stop is considered as
recognised. The home position is set in this position.
The direction in which the mechanical limit stop is searched for is specified by the sign of
the reference speed. In order to avoid damages on the mechanics or in the drive train, it is
recommended for this reference run to select the reference torque below the rated torque
of the drive.
If gearboxes are used and a greater output torque results from this, a reference run on an
end stop has to be checked thoroughly. In the case of an incorrect dimensioning, the limit
stops or the gearbox may suffer damage.