2 - Schneider Electric CZ, s.r.o.

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Presentation
SoMachine software &
Application Function Blocks library
Improving performance
Grab control
> > Industrial cranes
Typical applications
> > Industrial cranes.
Improve efficiency of your grab while reducing stress on
mechanics
This ready to use dedicated function block realizes the grab function controlling the 2
drives of the hoisting system (Hold and Close).
The best regulation mode is automatically applied according to requested Operation:
Closing, hoisting with synchronization, opening/closing the grab, etc
Benefits
Save production time
> > Efficient closing operation on material with less fatigue for the operator
(operation control with a single joystick).
Increase crane life
> > Reduce mechanical shocks and stress on the crane mechanism and structure
(by virtual limit switches)
> > Less wearing of cable and gearbox due to optimized control.
Save design time
Ready & Easy to use full Grab function dealing with the complexity of your crane
> > Only some parameters to set.
Reduce your cost
> > Drive I/Os are used as remote I/Os of the controller
> > Optimize sizing of motors and drives due to torque sharing during lifting
> > Short commissioning time.
Operating principle
The main objective is to control all working modes of the Grab function.
The Controller gets all information needed to achieve the control either through I/Os
connected to the drives either through onboard I/Os.
The controller is applying automatically at any time the relevant control to the drives.
No rope slack during closing on material due to torque monitoring.
> > Speed Control + Synchronization of up and down movement during empty or
closing and opening in the air.
> > Speed Control + torque balance when lifting with a load.
Characteristics
This Function block is designed to control Altivar 71 drives serie.
No extra encoder needed, The controller can get access to Encoder feedback
information connected to the drive.
> > For a more accurate control a load cell or a strain gauge can be used for closing
on material and slack detection
This function block can be used on controller type S of MachineStruxure TM
> > HMI function can be handle by Drive Keypad or Magelis Touch screen panel.
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2
3
4
5
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7
Close Hold
8
Set point Hold Speed Set point
Set point Close
Position Hold
Position Close
Grab
Control
Torque Hold
Torque close
Grab
Control
FW
RV
Speed Set point
Torque control
Torque control
FW
RV
Drive
hold
Hold
9
Drive
close
M DI
M DI
10
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