For most PLCs, SmartCrane offers a software library that implements open loop anti-sway plus automatic move to position.  Separate licenses required for destination pushbutton handling and closed-loop sway correction using customer-supplied swing measurements.

 

Software Libraries for PLCs

PLC SOFTWARE FEATURES

Manual Anti-sway

Requires Hoist Length, Operator Stick Demand (one dimension per instance), load weight OR hoist motor current, and brake demands ( for the chosen dimension).  Anti-sway will hold off brake closings until all sway removal movements are complete.   One license can support simultaneous bridge and trolley motion.

Automatic Move to Destination

Uses same anti-sway as Manual and will drive to the destination, within required tolerance, in minimum time without sway.

Destination Management 

Optional, separately licensed code responds to user buttons to save and retrieve destinations. User configurable for a mix of permanent and temporarily-saved destinations in two dimensions.  Delays moves until safe height is reached (Optional).  Follows a prescribed corridor when bridge is within a defined range of positions, to avoid collision with fixed structures or equipment (Optional).

                   


REPRESENTATIVE IMPLEMENTATION

(Bridge and Trolley)

               


S-Curve Velocity Smoothing

For proper anti-sway performance, the crane drives must follow the SmartCrane velocity profile precisely and any smoothing or adjustment to these reference signals must be turned off.  In cases where the operator cab moves with one or more horizontal crane movements, the user may wish to apply “S-Curve smoothing” by entering a non-zero value for the “accelRampTime” parameter.

TRAP Mode

Used with optional Closed Loop Sway Control, TRAP mode allows operator to signal when a swinging load is in the desired position: Closed Loop will return the load to that position without sway.

Conditions

PLC must accept C or Structured Text Code, must support encrypted libraries, and must supply access to secure machine identification.

 

OPEN LOOP INPUT


Control Codes:

Brake Off:

Velocity Demand:  

Input Time:  

Hoist Rate:     

Hang Length:    

Max Speed:    

Velocity Ramp Time:    

Crane Response:    

License Key or Code:


AUTO POSITIONING ONLY 


Current Position:

Destination Position:    

Lag Time:   

Tuning Parameters:


OUTPUTS


Velocity Reference:   

Brake Request:   

Control Code:

Move State:

Antisway Pending:

Error Code:


AUXILIARY SOFTWARE


DESTINATION MANAGEMENT


Inputs:

Outputs:

  

LOAD FROM CURRENT  

Input:

Output:


HANG CALIBRATION   


Input:

Output:


CLOSED LOOP CONTROL   


Input:

Output:



PLCs SUPPORTED:



0    Suspend, 1 = Manual Anti-sway, 2 = Move to Position, 7 = TRAP

1    Off

Ft/Second +/-

Seconds, floating point

(Optional) Ft/Second + UP

Feet, + DOWN, corrected for swing timing

Ft/Second

Seconds to reach Max Speed

(Optional) Crane Motion (Ft/Second): if unavailable, use small fixed value

Supplied by SmartCrane LLC based on CPU serial number


 


Feet, floating point +/-

Feet, floating point +/-

In seconds, normal lag in crane drive response

Determined from results of commissioning tests




Ft/Second +/-

1    Request release

Same as input, except -1=Input Error, -2=License Invalid, -3=License Expired

(0-6) Idle, Starting, Accelerating, Slowing, Stopping, Approaching, Final

REAL value only required for Closed_Loop input.

0-14, where 0 represents no error.  See Interface Manual.






Up to 16 boolean values for pushbuttons; hang length; time in seconds; corridor restrictions; permanent XY destinations. 

XY Destination commands for bridge and trolley antisway inputs; boolean lamp control signals for pushbutton lights.


  

Time in Seconds and hoist motor current. 

Estimated load on hook


   


Tuning parameters estimated during commissioning; load cell readings; real time measured rope length.

Calibrated pendulum length, separately for trolley and bridge.




Control code; PLC-supplied swing measurements; time in seconds; Antisway Pending.

Small-motion velocity reference; control code.



GE, ABB, Rockwell Automation (Allen-Bradley Add-On Instruction), Siemens, ifm Electric.

ANTISWAY FUNCTION BLOCK I/O REQUIREMENTS


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