Pulling cable through underground ducts used to be done by a gang of men, but these days special motorised winches are used. Those who lay the cable are required to provide records showing distance pulled and tension in the cable. This is especially important with filber optic cable which is not very robust and which can cost up to £ 36,000 per reel. We were approched by SEB International Limited to devise a universal recorder for their range of cable-pulling winches. The recorder was given the name of WinchMaster by SEB and is a complete stand-alone unit, operated via a keypad and liquid crystal display and requires only a standard 12volt engine battery for operation. It is fitted with a tally-roll printer and, as an optional extra, can be connected to a PC for downloading recorded data. WinchMaster uses a rotary encoder for measuring rope pull distances and a pressure transducer for monitoring the drive’s hydraulic fluid pressure. An inbuilt equation accurately converts the pressure into units of tension in the winch cable. The system is factory-configured for use with different types of winch. A user-entered overload factor prevents the winch from applying too much tension to the cable and a 12volt output operates a cut-off solenoid. Computer downloads are achieved using a special cable and a PC software program. The Recorder is based on a Motorola microcontroller. The program (firmware) is burnt onto the system, but the recorder can store configuration settings in non-volatile memory and other variables in conventional memory. The system can therefore be configured for routine operation and will retain settings even when the power is turned off. It contains a millennium-compliant battery-backed real-time clock/calendar (RTC). The date and time are used to identify recordings. The recorder is available with a data storage capacity equivalent to 10,000 metres of cable, recording every 5 metres. The controller is operated manually using the inbuilt keypad and liquid crystal display. The computer connection is used only for configuring the recorder or downloading data. When connected in this way the in-built printer is automatically disabled. |
