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         wire rope terminated with a thimble and swaged clamps,
         or a swaged purpose built fitting. In yet another example,
         guide wire 6 may be mounted to wire rope termination de-
         vice 22 via a welded connection. In turn, wire rope termi-
         nation device 22 may be anchored to tower 2 via threaded
         connection that is mounted in the concrete or metal base of
         tower 2. In other examples, wire rope termination device 22
         may be mounted to tower 2 via a weld, rivets, or any other
         suitable anchoring system.                           Figure 17: Schematically a method for calibrating an incremental rope
           Figure 15 is a schematic view of tension loss sensor 14,   distance signal.
         continuity plug 20, continuity test device 32, battery 28, ten-  to the wire rope 12, however, permanent attachment is not
         sion system spring 18, wire rope termination device 22, and   essential to the invention. The wire rope 12 is positioned ad-
         guide wire 6. In one example, such as the examples of figure   jacent an Incremental Rotary Encoder 20 and a sensor head
         15, continuity plug 20 is located proximal, within the same   30, which are components of the apparatus 10 that define
         confined space, to tension loss sensor. In another example,   a measurement path for the wire rope 12. The incremental
         continuity plug  20 is arranged separate  from tension loss   rotary encoder 20 produces an Incremental Rope Distance
         sensor  14 and the components are communicatively con-  Signal 22 (e.g., a sequence of pulses 24 as shown in figure
         nected. For clarity, the other components of guide wire ten-  17, each pulse corresponding to a full or partial rotation of
         sion assembly 4 and tower 2 have been removed in figure 15.   a  rotary  encoder  wheel  26)  that is  subject  to  inaccuracies
         As illustrated,  tension  loss  sensor  14  includes  battery  28.   as described above. The sensor head 30 can be a magnetic
         Figure 15 is intended to show how the various electrical, me-  sensor head, for example of a type as conventionally used
         chanical, and logical connections of the different components   for magnetic non-destructive examination (“NDE”). The sen-
         of guide wire tension assembly 4 work together. In other ex-
         amples according to this disclosure, a guide wire tension as-
         sembly 4 may include fewer components. In such example,
         guide wire tension assembly 4 may not include continuity
         test device 32.

         Method  and apparatus  for wire rope distance mea-
         surement
         Pat.  9,791,301  U.S.  class  G01D  5/24452    Int.  class  G01N
         27/60
         Inventor: Herbert R. Weischedel, South Windsor, CT.
         Assignee: NDT Technologies, Inc., South Windsor, CT.  Figure 18: First exemplary loss of metallic cross-sectional area (“LMA”)
                                                              traces.
           Measuring distance along a wire rope, by steps that in-
         clude moving the wire rope across a sensor head; counting
         rotations of a rotary encoder driven by the moving wire rope;   sor head 30 continuously produces an NDE signal 32, e.g., a
         detecting a first distance marker crossing the sensor head at   magnetic inspection signal that is used for the detection and
         a first position of the wire rope; detecting a second distance   evaluation of rope deterioration. In order to calibrate the in-
         marker crossing the sensor head at a second position of the   cremental rotary encoder 20 for reduction of inaccuracies,
         wire rope; and establishing calibration parameters for pro-  the apparatus 10 also includes a distance calibrator 40 that
         ducing a calibrated distance measurement corresponding to   is operatively connected to the incremental rotary encoder
         any output of the rotary encoder, based at least on correlat-  20 (for sensing the incremental rope distance signal 22) and
         ing a known distance between the first and second distance   to the sensor head 30 (for sensing the inspection signal 32,
         markers to a counted number of pulses of the rotary encoder   including indications 52 of the distance markers 14).
         between the first and second positions of the wire rope.  FIGS. 3-4 show schematically a method 50 for calibrating
           Figure 16 shows a functional block diagram of a distance   the incremental rope distance signal 22. In certain embodi-
         calibration apparatus 10, according to a first embodiment of   ments, the distance calibration apparatus  10 implements
         the invention. The inventive apparatus 10 is configured for   the method 50. As one step of the method 50, the distance
         use with a wire rope 12. According to a typical embodiment,   calibrator 40 continuously senses the inspection signal 32
         the wire rope 12 carries at least two distance markers 14,   that is output from the sensor head 30, which detects 52 the
         which are spaced apart at a well defined known distance,   distance markers 14 as they move through the sensor head
         D. The distance markers 14 can be permanently attached   30. As another step 54 of the method 50, the distance cali-
                                                              brator 40 counts pulses 24 of the incremental rope distance
                                                              signal 22 of the incremental rotary encoder 20. The distance
                                                              calibrator 40 then calculates 56 a length of wire rope, d be-
                                                              tween each of the incremental pulses 24, d=D/N based on a
                                                              number, N, of incremental pulses counted between distance
                                                              marker detections 52. In case the leading edges of the dis-
                                                              tance marker detections 52 and of the incremental pulses 24
                                                              coincide, as shown in figure 17, then the distance between
                                                              pulses d=D/N exactly, as indicated in figure17. However, in
                                                              case the leading edges of distance marker detections 52 do
                                                              not coincide with the leading edges of incremental pulses 24,
         Figure 16:  Functional block diagram of a distance calibration
         apparatus.                                           then d can be interpolated. In this case, it can be assumed

         64     Wire Rope News & Sling Technology   April 2018
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