A method for determining the length of a line involves determining a length of a first electrical line, determining an identifier of the first electrical line, determining a length of a second electrical line, which is intended for installation in an electrical installation assembly, based on the length of the first electrical line and a starting length determined by means of the identifier.

A method for use in measuring a property of an environment or an object in, or adjacent to, an elongated space (10), comprises unspooling and/or spooling a line (6) attached to a tool (4) so as to move the tool along an elongated space. The method may comprise using the tool to measure a property of an environment or an object in, or adjacent to, an elongated space during movement of the tool along the elongated space. The method may comprise, determining an acceleration of the line, measuring an acceleration of the tool along the elongated space, and controlling damping of the movement of the tool along the elongated space according to the measured acceleration of the tool and the determined acceleration of the line. The elongated space may be located downhole or may be defined in, or adjacent to, an oil or gas well.

Measuring distance along a wire rope, by steps that include moving the wire rope across a sensor head; counting rotations of a rotary encoder driven by the moving wire rope; detecting a first distance marker crossing the sensor head at a first position of the wire rope; detecting a second distance marker crossing the sensor head at a second position of the wire rope; and establishing calibration parameters for producing a calibrated distance measurement corresponding to any output of the rotary encoder, based at least on correlating a known distance between the first and second distance markers to a counted number of pulses of the rotary encoder between the first and second positions of the wire rope.

A belt assembly includes a belt retractor, a sensor having a detection field, and a belt retractably payable from the belt retractor through the detection field. The belt has a webbing and a plurality of markers fixed to the webbing. The webbing has a longitudinal length and the markers are equally spaced along the longitudinal length of the webbing. The sensor senses the length of the webbing paid out. A size of the occupant may be determined based on the length of the webbing paid out, and the size of the occupant may be used to classify the occupant in classes.

Embodiments described herein provide a system for cable length measurement in a communication system. The system includes a transmitter, a receiver, a signal sampler and a cable length calculation unit. The transmitter is configured to transmit a plurality of data symbols at a first data rate via a wired data communication link, and the receiver is configured to receive a reflection signal. The signal sampler is configured to sample the received reflection signal using a phase shift number of shifting sampling phases to generate reflection samples, and combine the reflection samples with different sampling phases to generate a series of reflection samples corresponding to a second data rate higher than the first data rate. The cable length calculation unit is configured to determine a delay parameter from the series of reflection samples, and generate an estimate of a length of the data communication link.

Cable-actuated position sensors are described that employ multiple block and tackle arrangements to measure displacement of a draw wire or flexible cable. The disclosed sensors are relatively small and inexpensive. The disclosed sensors may also be used as part of a servo motor, or in conjunction with gear motors to provide positional information for operation of the gear motor.

The invention relates to a chain elongation monitoring device having a first differential transformer, a second differential transformer, and a control for recording the measured values, wherein the second differential transformer is arranged at a fixed distance from the first differential transformer, and a method for operating the chain elongation monitoring device.

Winch (304) has a load bearing tape (305) to advance into a borehole (307). Hole depth can be determined by subtracting a sensed height (310) above ground surface (311) from total depth (312) measured. Can include a height above ground sensor (314) and a tape distance measurer (316). Depth of water or watery mud or muddy water (320) can be sensed, such as by a pressure sensor (326) on a weight or in a sensor device at or near the tape leading end. A heater (309) can warm the tape. A cover or housing (313) can be provided for the winch or spool. The tape can include wires or fibre optics (336) embedded in or applied to a surface of the tape (305) and/or apertures or embedded or surface applied markers/indicators (338) along a length thereof e.g. for reading by an optical or magnetic sensor.

A cable measurement system and cutter apparatus has a housing, a display device, a material conduit, a rotary encoder, a cutting tool handle a resistance member a movable cutting blade and a blade aperture. The cutter system is able to measure the length of a cable that passes through the material conduit which traverses through the housing. The display device is mounted onto the housing and is coupled to the rotary encoder which measures the length of cable passed through the housing. The encoder is mounted next to the conduit so that the cable is measured, and the length is displayed on the display device. one end of the cutting tool handle is rotatably mounted to the housing and the movable blade is mounted onto the opposite end of the handle. The blade is able to cut the cable by moving through the blade aperture which traverses through the conduit.

An apparatus for measuring wire and cable length is provided for using a wireless encoder for wire and cable processing. The apparatus for measuring wire and cable length may include a housing, battery, communication component, microcontroller, printed circuit board, encoder module, encoder disc, shaft, wire counter and spool.