DIGITAL SHAFT SET WJG-1

GENERAL CHARACTERISTICS

WJG1
fig.1. Digital Shaft Set WJG-1

Digital Shaft Set WJG-1 is a set of microprocessor devices dedicated to employ in mining winding gear to:

For high safety of operation the WJG-1 uses different sources of input information to project the position:
  • one absolute position encoder
  • one incremental position encoder
  • magnetic switches as correction points in the shaft

Due to incorporating the absolute position encoder the device is entirely resistant to power down conditions. Both encoders can be mounted on rope wheel or on the drum shaft (separately or as a combine unit), incremental encoder can be mounted directly on motor shaft. The best configuration is: absolute encoder on rope wheel, incremental encoder on motor shaft (can be used as a digital speed feedback).

An important advantage of WJG-1 is that it can be randomly programmed by means of a PC computer service software to dynamically adjust essential shaft & winding gear operating parameters according to actual needs. Internal software of CPU run its own safety procedures which enable continuous supervising of proper programme loops' course and generate an error signal in case the WJG-1 is unable to accomplish its functions.

BASIC STRUCTURE

This is a modular unit enabling connection of different peripheral devices in needed configuration and quantity. The whole device consists of three major units:

  • The CPU unit with basic parts:
    • Microprocessor board
    • Communication port board
    • Binary inputs' board
    • Encoders' operation board
    • Service link board (serial link to PC computer)
  • The absolute & incremental encoder unit
  • The set of peripheral devices. These devices are:
    • A/C & C/A converters
    • Digital displays
    • Analog (moving point) displays
    • Relay modules (8 or 16 per module)

Thanks to their internal structure and the transmission protocol employed between the CPU and peripheral devices these modules can be placed of up to 100m from the CPU unit. Each of these modules is equipped with a correct work supervision circuit along with an error signalization relay.

POSITION POITER

The WJG-1 is equipped with at least two different elements which display the actual conveyance position within the shaft:

  • rough position pointer - ''moving point'' pointer which displays the position with an accuracy not worse than 10m
  • exact position pointer - digital display which displays the position with an accuracy of 1cm.

SPEED POINTER

A digital speed pointer for indicating the actual speed is employed as an additional function. The WJG-1' CPU unit calculates the conveyance's speed on the basis of input pulses obtained from the encoders.

ROUTE PROGRAMMER

Digital Shaft Set WJG-1 can be equipped (as needed) with relay module/s (8 or 16 relays) to discrete project the position in form of binary signals to indicate the presence of the cage in certain points or zones within the shaft.

OVERSPEED CONTROL

WJG - 1 is capable of storing up to 16 different so called ''permitted speed envelopes'' (flangers) in its memory. These envelopes (flangers) are stored in form of speed/position diagrams and the choice of the hoist's operating mode causes one of these diagrams being active. Depending on the position the WJG-1 control programme gets the appropriate value from the active envelope's (flanger's) table and transmits it to C/A converter where it is converted into analog value (0-10 V) and output. Additionally the ''permitted speed envelope'' (flanger) serves for software speeding control which is performed by continuously comparing the conveyance's speed with the value taken from the ''permitted speed envelope'' (flanger) table - when the speed exceeds the permitted speed value WJG-1 generates an error signal which enables emergency stop of the winding gear.

SAFETY PROCEDURES

WJG1
fig.2. ''Szybpar'' service software screenshot

WJG-1 performs multiple self-test functions in order to protect the winding gear against dangerous situations. These functions are as follows:

  • continuous jump check
  • correction point jump check
  • rope slip check generated
  • rope wheel diameter check
  • Kinematics connection check
  • Magnetic switches operation check
  • Speeding control
  • Self-test - every part of WJG-1 performs its own self-test procedure

SERVICE SOFTWARE

The Digital Shaft Set WJG-1 is equipped with a specialized software module for dynamically programming several shaft's and winding gear's parameters and factors which are saved in the EEPROM memory of the WJG-1. The programme works on a PC computer and communicates with the WJG-1 by means of a serial link. It is also possible to dynamically changing the depth of the shaft displayed on the displays locally by means of two switches available one the machine's console. This function is useful in the applications working with shafts being sunk. The changing of the shaft's depth function automatically changes the characteristical points of the ''permitted speed envelope'' which are associated with shaft landing position in order to reduce the speed of the gin tube in working zone. Above described function can also be logically associated with moving the switching points of all or some relays on the relay module (when needed).

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