View source for Project Example: Label Machine (Ladder Diagram)/zh-hans

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The task is to place a label at a particular position on a product. <br/>
The application has two drives: one to feed the product via a conveyor belt, the other to feed labels and to place them on the moving products.<br/>
The labeling process is triggered by a position-detection sensor.<br/>
From the detection of the product to the start of the label movement, there is a delay that depends on the velocity of the conveyor, the position of the sensor and the position of the label on the product. 
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[[File:Label Machine.PNG|border|600px]]  
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Both axes move with the same velocity set point. <br/>
The delay for TON FB is calculated from the sensor distance and the velocity. After a labeling step, the Label Drive stops again and waits for the next trigger, while the conveyor continuously moves.
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The main program initializes a startup process in the softMC. <br/>
After the startup process is done, the program sets 'Done' variable and a global variable. <br/>
After 'Done' variable is set, program 'Labeling' is called. <br/>
The application uses two drives and their outputs. <br/>
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After installation of device description file (created by the Configurator) to Device Repository, the drive's address will be declared in the Axis Pool:

[[File:Label A1.PNG|border|600px]]           [[File:Label A2.PNG|border|600px]]
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In the EtherCAT Slaves section, we can find the I/O mapping for each device.<br/>
In the picture below Input1, Input2, Input3, Input4, Input5, Input11, Output1, Output2, Output3, Output4 and Output5 are declared as new variables (can also be mapped as existing variables):

[[File:Label CDHD I_O.PNG|border|600px]]
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The main program uses 'softMC_Startup' FB ('mc_st' Instance) to initialize a startup process in the softMC.<br/>
A rising edge detection will set the 'Done' variable (and also a global variable) and then call program 'Labeling':

[[File:Label main program LD.PNG|border|500px]]
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==Labeling POU - Declaration Section==
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The declaration section in the Labeling program contains the following instances (as shown in the next picture):<br/>
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1. '''MC_POWER_01 -''' an instance of MC_Power FB.<br/>
This Function Block enables/disables an axis.<br/>
If the axis is associated with a real drive, a state machine is invoked to enable/disable the drive via PDO.<br/>
If the axis is simulated, a MC-Basic subroutine is invoked to enable/disable the axis.<br/>
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2. '''MC_MoveVelocity_01 -''' an instance of MC_MoveVelocity FB.<br/>
This Function Block commands a never ending controlled motion at a specified velocity.<br/>
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3. '''MC_halt_01 -''' an instance of MC_halt FB.<br/>
This Function Block commands a controlled motion stop. The axis is moved to the state ‘DiscreteMotion’, until the velocity is zero. With the ‘Done’ output set, the state is transferred to ‘Standstill’.<br/>
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4. '''MC_MoveRelative_01 -''' an instance of MC_MoveRelative FB.<br/>
This Function Block commands a controlled motion of a specified distance relative to the set position at the time of the execution.<br/>
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5. '''labeling_timer -''' an instance of TON FB (On-Delay timer).

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[[File:Label Axis declaration.PNG|border|1300px]] 


==Labeling POU - Implementation Section==
Output5 is turned on when Labeling POU is called.<br/>
Input1 (of both drives) will turn on Output1 (of both drives).<br/>
Input2 (of both drives) will turn on Output2 when Output1 of drive 2 is on (of both drives).
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If Output1 is triggered, the MC_Power FB is enabled (for both drives). <br/>
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[[File:Label Axis implementation LD.PNG|border|700px]]
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If drive 2 is enabled and Output2 of drive 1 is on, then Axis 2 will rotate in a constant velocity. <br/>
Input3 of drive 1 is the product sensor detection input.<br/>
If Output2 of drive 1 is on, then a timer will start counting when Input3 of drive 1 is turned on for 'timing' (PT) seconds.<br/>
In addition, a calculation of the time delay is inserted into 'delay_real' and then converted from 'real' units to time units.<br/>
When the timer has elapsed (Output2 is still on and drive 1 is still enabled), axis 1 will move in the configured 'label_length' distance.<br/>
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[[File:Label Axis implementation1 LD.PNG|border|600px]]
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When a falling edge is detected in Input2 of drive 1 or drive 2, then a boolean variable 'stop_motors' is  triggered. <br/>
If drives are enabled, then when 'stop_motors' is TRUE, the MC_halt FB is executed.<br/>
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[[File:Label Axis implementation2 LD.PNG|border|700px]]
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==Visualization==

The program is controlled by a graphic interface:
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[[File:Label visualization.PNG|border|700px]]
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When the startup process of softMC is done, the blue lamp is turned on.<br/>
The user can turn on and off Inputs 1 - 2 for each drive and watch their status in the green lamps.<br/>
The product sensor detection input can be turned on (Input3 of drive 1).<br/>
The distance, delay time and velocity are displayed by graphic meters.