Petro-chemical Cranes Automations


Coker Crane Solutions - Application Design

Automation

General

A coker crane consists of a mechanical grab controlled by two machineries, one for hoisting and one for closing: the trolley and the bridge. All motor drives are controlled via field bus (Profibus) in normal operation or hardwire controlled frequency converters (inverters), DynaHoist for hoisting and closing and Dynac for trolley and bridge. The traveling hopper is also controlled via field bus. All crane functions are controlled by PLC except from the hardwired backup control place (pendant).

Crane movements and functions are controlled from the driver’s cabin. For service purposes, the system has a backup control place (pendant) to make service of the crane easier (e.g., changing of the ropes).

Main Functions

  • Control of the grab motions (DynAGrab double machinery grab control system)
  • Control of the trolley motions
  • Control of the bridge motions
  • Control of the power supply functions, such as the main contactor, air conditioning etc.
  • Control of the semi-automation
  • Control of the traveling hopper motion
  • HMI interface, such as alarms, events, process information etc.

Control System

Main components

The main components of the PLC system are:

  • Master PLC in the electric room
  • Dual power supply
  • CPU S7-400 Fail-S
  • Critical I/O to S7-400 rack, doubled
  • Remote I/O units in the control room, in the trolley and in the operator’s cabin
  • Field bus or hardware controlled inverters in the electric room
  • Operator panel, HMI in the operator’s cabin and electric room
  • Position measurement encoders for the trolley and the bridge
  • Field bus from the electric room to the bridge, trolley and operator’s cabin
  • Fiber optic cable from the electric room to the junction box, which located to building side
  • CMS, crane monitoring system

Motor drives

The motor drives are KC Dynac and KC DynaHoist frequency converters (inverters). In manual mode movement, the bridge is controlled with a stepless (0-100%) joystick from the operator’s cabin. In backup mode, movements are controlled with two-step control buttons from the pendant.

DynaReg, a regenerative braking system

DynaReg is a regenerative braking system, which feeds power generated by motors in braking back to the network.

Traveling hopper

The traveling hopper driving is controlled by separate pushbuttons from the operator cabin. In service mode, it is not possible to drive the traveling hopper.

Crane bridge drive synchronization, DynATrak/P ( / R)

General

Synchronization of the crane bridge drives is normally achieved through the mechanical structure of the crane being sufficiently stiff/strong to prevent any excessive misalignment. Where cranes are of large span or where the drives are significantly differentially loaded, the drives can respond differently and could thereby cause a skew effect to develop on the crane. An electrical DynATrak synchronization ensures that the crane moves smoothly along the track without building up skew.

DynATrak/P refers to proportional measurement of alignment. In proportional measurement, the absolute position of the bridge ends on the runway is not known, but alignment is checked at several check points placed on the runway and correction is done based on the last measurement point.

The Konecranes DynaTrak/P solution is as follows:

Dynac inverter drives run along each side of the crane, which allows speed adjustments to be made to each side independently to prevent excessive misalignment.

Communication to DCS

The crane exchanges data with the customer’s DCS system. Communication is done via Profibus DP. The amount of data is 128 bytes/direction.

HMI

The system consists of PLC and the operator panel. Communication between PLC and panel is done via field bus. All registers of the data are located in the PLC. All alarm and event texts and alarm and event histories are stored in the memory of the operator panel.

KC DynAMonitor screens typically consist of the following data areas:

Main screen

The main screen is presented on the right. The main screen provides access to the other screens, which are related to the grab control. The screen is selected by pushing the blue button.

The ESC button is used for moving to a higher level in the screen hierarchy


DynAGrab double machinery grab control system

DynAGrab control, developed by Konecranes, is designed for grab unloaders and other cranes where a mechanical grab is operated by two rope systems. DynAGrab control consists of two DynAHoists, a programmable logic controller (PLC), sensors, limit switches, and devices for the user interface (for detailed information, see specification DAGPF10.PDF).

DynAGrab control features

  • Synchronization
  • Load Balancing
  • Automatic Grab Filling
  • Fast Stop
  • Fault Detection
  • Grab Jammed Detection

DynAPilot, electronic antisway control

The antiswing system DynAPilot prevents load sway caused by crane movements and makes the crane easier to operate. With the antiswing system, the crane operator controls the load movements directly, and load swing is prevented automatically.

Automation types

  • Semi-Automation for “Go-to-Hopper” and “Return-to-Previous-Position” helps navigate in poor visibility situations
  • Part-Time Full Automation can be used in low-visibility situations
  • Full-Time Full Automation, operating independent of visibility conditions, is available
  • Automated Cranes can be monitored from the Coke Unit control room
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