Technical Application Notes

Transcription

1 Technical Application Notes Programming ControlLogix-Based Systems to Perform Product Tracking Purpose of this document: To provide the OEM machine designer with a guide to programming/implementing product tracking functions into ControlLogix-based packaging and material handling applications. The document discusses both basic and advanced methods of product tracking. NOTE: This application document as written uses Version of SoftLogix to simulate different tracking scenarios and solutions. This document is motion-intensive, and has been developed for use with Kinetix hardware & software architectures. It is not intended for use with other control architectures. Application Description: Most packaging applications require some sort of product tracking routine. These tracking routines can be as straightforward as assuring that a machine has inserted one product into one box. More advanced features might include tracking such activities as adding coupons or leaflets to the carton or box, not gluing an empty or misaligned carton, or assuring ingredients are not added to a defective container. This document describes three types of product tracking scenarios based on Logix products. Each solution will provide a more challenging programming exercise than the last. By presenting several examples of product tracking routines, we intend to provide the OEM designer with a clearer understanding of how these solutions can be applied across a variety of applications. Understanding product tracking scenarios Product tracking can make use of different methods to accomplish the same end result. However, certain routines or instructions are better suited for specific applications. This document attempts to explain where each of the following routines can be used to their advantage. Bit Shift Left / Bit Shift Right Instructions (BSL/BSR) This routine shifts the specified bits within an array one position left or right depending on the instruction used and is used for simple product tracking of one item per shift. First in First out Instructions (FFL/FFU). This routine shifts the specified words within an array from the highest array position to lowest, and is used when multiple items (or lack there of) are being tracked at one time. The Copy instruction can do this as well. Copy Instruction (COP). This instruction can be used across a multitude of applications as will be shown throughout this document. It is used when an array of items or a recipe array must be tracked

2 Bit Shift Left and Bit Shift Right Instruction The BSL instruction shifts data to the left, Once the BSL instruction has completed, all bits in the 10- bit pattern will have been shifted left by one. Each time the instruction is executed, the entire array parameter data will be shifted to the MSB (Most Significant Bit) by one. Conversely, the BSR instruction shifts data to the right. When using the BSR instruction, data is entered into the MSB. For example, if the array was ten bits long, then the data would be entered into bit nine. Depending on how long tracking must take place, multiple words can be used to track for longer distances. This will be shown in Application One Before Bit Shift After Bit Shift Data entered at bit zero Application #1 - Product Tracking Using BSR/BSL This application illustrates a direct method to track product using a Bit Shift Left or Bit Shift Right Instruction. This application will assume one product is displaced at a time. In this example, product tracking has been implemented to insure a box is not put down unless there is product present. An example where this routine can be used might be in a continuous motion cartoner application. Product is moving down a conveyor in buckets, and cartons or boxes are placed in coordination with product presents. The next few pages will explain how to setup the application, create BSR and BSL, and create starting point for an array shift. Step 1: Setup Application In this Scenario we are tracking dispensing of product into a carton followed by gluing the carton. We will assume the following. The Sensor to track product is 20 stations from carton feeding system. The Glue system is 16 stations from carton feeding system. A total of 36 bits are needed for tracking. Product Detect Sensor Carton Feed System Glue Application Area Machine Bucket Number DINT[1] DINT[0] 2

3 Step 2: Create BSR/BSL In this Scenario we will create a BSR instruction Create an array of type DINT (For every 32 bits there will need to be another word associated to this. In this application the array size needs to be two words in length. Create the Control word of type CONTROL Create the source bit of type BOOL Set at the length of bits you want to track (or higher). In this example, bit length will be set to 36. Step 3: Create Starting Point for array shift We are product tracking using a BSR instruction the Control Bit(s) shift from MSB to LSB. The Source Bit will be shifted into the BSR_ARRAY_WORD at word one of bit three. This is shown below. Exit Point Not Used Enter Point This bit will enter at bit three (4 th bit) of word one, wrap around to word zero, entering at bit thirty-one, exiting at bit zero of word zero. Step 4: Demonstrate Application We will assume there is one axis running the entire system and every 360 degrees of the axis is one product. So we need to examine the source bit every 360 degrees to see if we have product or not. This is shown below Application #2 - Product Tracking Using FIFO or Copy Instructions In some cases there is more involved than shifting of one item. If there are inserts, more than one item or box, etc. per product, then using multiple bit shifts becomes inefficient. This is where the FIFO or Copy instructions come into play. These instructions can shift entire 3

4 words at one time. Each bit can accommodate an item or lack there of. For example, each DINT consists of 32 bits; each of these bits can represent something in the array. In this application we will add on to Application # One by inserting two sets of instruction leaflets into each box. We then need to track to determine if these were added. If any of these items are missing, then the box should not be glued. This routine will inform the machine operator that an item is missing, and that the machine needs to be inspected. The next few pages will explain how to set up the application, create FL/FFU, assign bits for each point, and will demonstrate the application. Step 1: Setup Application In this Scenario, we are tracking product as it is being loaded into a box, and adding two information leaflets before the box is glued. We are using the following starting criteria: The sensor to track product is 20 stations from carton feeding system. Leaflet # One is 2 stations from carton feed Leaflet # Two is 3 stations from carton feed The Glue system is 16 stations from carton feeding system. A total of 36 DINT S are needed for tracking Leaflet one feed Sensor Leaflet two feed Sensor Product Detect Sensor Carton Feed System Glue Application Area Machine Bucket Number DINT 35 DINT 34 DINT 33 DINT 32 DINT 31 DINT 30 DINT 29 DINT 28 DINT 27 DINT 26 DINT 25 DINT 24 DINT 23 DINT 22 DINT 21 DINT 20 DINT 19 DINT 18 DINT 17 DINT 16 DINT 15 DINT 14 DINT 13 DINT 12 DINT 11 DINT 10 DINT 9 DINT 8 DINT 7 DINT 6 DINT 5 DINT 4 DINT 3 DINT 2 DINT 1 DINT 0 Step 2: Create FFL/FFU Instruction Create an array of type DINT in the FIFO field. In this application make an array size of 50. Create the Control word of type CONTROL Make the length size. Set the length to the length of your array size. In this case it will be 50. Set the position to 35. This is where the first DINT is loaded into the array DINT[35] For the FFU instruction use all of the same variables for everything except the DEST. Create a variable of type DINT. When the FIFO unloads the data into array DINT[0], it is then shifted to the GARBAGE DINT. Note: FIFO Instructions shift data from MSB to LSB 4

5 Step 3: Assign bits for each point In this scenario the following bits are assigned accordingly in the DINT Array Product Sensor Detect : Bit 0 Carton Feed System: Bit 1 Leaflet one Feed Sensor: Bit 2 Leaflet Two Feed Sensor: Bit 3 Glue Application Area: Bit 4 No Leaflet 1 at Feed Sensor Bit 5 No Leaflet 2 at Feed Sensor Bit 6 When a product is detected, the FIFO DINT array have a one in bit zero as shown below If there is product present, tell the system to load a carton. Once the carton is loaded, move a one in bit one as shown below Now that a carton has been loaded, leaflets are ready to be loaded into the box. This is indicated by Bit 2 and 3 as shown below. Note: If leaflets from one or two are not available when the carton passes by, then move a one into bit five or six. This will tell the system not to send this package without inspection. Also, these bits can be counted at the end to tell the operator how many good packages vs. how many bad (no leaflets, no cartons etc.) Once all product and leaflets have been loaded, the system can look at all bits and determine whether to glue the box or not. If any one of these bits are not satisfied, then the machine can acknowledge this by not gluing the final product and rejecting it to be inspected. 5

6 Step 4: Demonstrate Application Below is a SAMPLE of detecting the product, loading and unloading of the FIFO instruction, and loading of leaflet feeder one. We will assume there is one axis running the entire system and every 360 degrees of the axis is one product. So we need to look at the Source bit every 360 degrees to see if we have product or not. 6

7 Application #3 - Product Tracking with build data sets using User Defined Tags and Copy Instructions Product Tracking can also involve sets of items that make up an individual product. This product can have options which are recipe driven depending on customer requirements. This is where UDT s (User Defined Tags) come into play. We create a recipe of user defined tags of every option needed for this product. Then we track to assure these items have been placed in the final package as it moves down the line. This application will demonstrate how this is accomplished. The next few pages will explain how to set up the application, create User Defined Tags, create Copy Instruction for this application, and will walk you through the application Step 1: Setup Application In this scenario, we are tracking a main package and adding multiple recipe parameters to the finished product. Up to five accessories can be added to the main package. Main Sensor to detect product and read designated customer recipe Five stations for accessory insertion Final product placed into box for shipping Glue final box Recipe Select One Recipe Select Two Carton Feed System Product Detect Sensor/ Recipe Select Three Barcode Recipe Reader Recipe Select Four Recipe Select Five Machine Bucket Number UDT Array 35 UDT Array 34 UDT Array 33 UDT Array 32 UDT Array 31 UDT Array 30 UDT Array 29 UDT Array 28 UDT Array 27 UDT Array 26 UDT Array 25 UDT Array 24 UDT Array 23 UDT Array 22 UDT Array 21 UDT Array 20 UDT Array 19 UDT Array 18 UDT Array 17 UDT Array 16 UDT Array 15 UDT Array 14 UDT Array 13 UDT Array 12 UDT Array 11 UDT Array 10 UDT Array 9 UDT Array 8 UDT Array 7 UDT Array 6 UDT Array 5 UDT Array 4 UDT Array 3 UDT Array 2 UDT Array 1 UDT Array 0 Step 2: Create UDT parameters Create a UDT Structure called UDT_RECIPE_SELECT Create Five Items in the UDT of type BOOL. Each item is for an accessory to be added to the main product. Create two tags of type UDT_RECIPE SELECT. Call the first tag Recipe_Track_Array. Make this an array of Fifty. Call the second tag Recipe_Source. 7

8 Step 3: Create Copy Instruction Create two copy instructions. The first will load the recipe parameters into the recipe tracking array. This will tell the system what product need to be loaded into the main package. This will take place when the product is sensed and barcode is read. The second Copy instruction is used to track the product and recipe product parameters as it moves down the line. Each product can have different recipe parameters. When the product arrives at each recipe station, it looks at the given recipe array and determines whether or not that particular item needs to be added to the final package. A sample of this is shown below. 8

9 Step 4: Demonstrate Application Below are samples of the Copy instructions for loading the recipe data and product tracking of the data. We will assume there is one axis running the entire system and every 360 degrees of the axis is one product. So we need to examine the source bit every 360 degrees to see if we have product or not. This is illustrated below. Note: This can also be done in Structured Text Important User Information Solid state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (Publication SGI-1.1 available from your local Rockwell Automation sales office or online at describes some important differences between solid state equipment and hard-wired electromechanical devices. Because of this difference, and also because of the wide variety of uses for solid state equipment, all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable. In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment. The examples and diagrams in this document are included solely for illustrative purposes. Because of the many variables and requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the examples and diagrams. No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software described in this document. Corporate Headquarters Rockwell Automation, 777 East Wisconsin Avenue, Suite 1400, Milwaukee, WI, USA, Tel: (1) , Fax: (1) Headquarters for Allen-Bradley Products, Rockwell Software Products and Global Manufacturing Solutions Americas: Rockwell Automation, 1201 South Second Street, Milwaukee, WI USA, Tel: (1) , Fax: (1) Europe/Middle East/Africa: Rockwell Automation SA/NV, Vorstlaan/Boulevard du Souverain 36, 1170 Brussels, Belgium, Tel: (32) , Fax: (32) Asia Pacific: Rockwell Automation, 27/F Citicorp Centre, 18 Whitfield Road, Causeway Bay, Hong Kong, Tel: (852) , Fax: (852) Headquarters for Dodge and Reliance Electric Products Americas: Rockwell Automation, 6040 Ponders Court, Greenville, SC USA, Tel: (1) , Fax: (1) Europe/Middle East/Africa: Rockwell Automation, Brühlstraße 22, D Elztal-Dallau, Germany, Tel: (49) , Fax: (49) Asia Pacific: Rockwell Automation, 55 Newton Road, #11-01/02 Revenue House, Singapore , Tel: (65) , Fax: (65) Publication RA-AP003A-EN-P August, 2003 Copyright 2003 Rockwell Automation, Inc. All rights reserved. Printed in USA. 9