Chapter 1 Quality Alert System (QAS) Overview

Transcription

1 Chapter 1 Overview In This Chapter Introduction to QAS QAS Components Tracking Image Types of Stations Summary 1 of 16

2 Overview Introduction to QAS Introduction to QAS The functions of QAS are as follows: Provides vehicle sequencing that displays vehicle ID on Performance Feedback System (PFS) terminals in sequencing stations Sequences vehicle IDs for marriage with tool data in Plant Floor Communication System (PFCS) Provides Automatic Line Stop (ALS) capability to contain problems within a station or production zone Notes: 2 of 16

3 Role of QAS The role of QAS is to positively associate the vehicle with process results and to contain a problem in station, rather than at the end of the assembly process. Fixing problems within the production zone in which they occurred is done because: It is easier to correct an assembly problem in the conveyor area where it occurs rather than to wait until the vehicle is completely assembled. The stop in real time allows the repair teams and engineers to consider and locate the primary cause of the problem. It avoids many vehicles being built with the same problems and is more cost effective than disassembling them later for repairs. Benefits of QAS QAS provides the following benefits: Helps minimize, detect, and contain vehicle build errors Reports vehicle location through the plant process Assists in automatically collecting and reporting process information by positively associating the vehicle with the information Improves error proofing and mistake proofing by positively associating the vehicle with the component being verified Minimizes defects by using ALS to prevent a defective part from leaving the station or production zone Continued on next page 3 of 16

4 QAS Components Introduction QAS components vary, depending on the plant, procedures, and processes being monitored. The components can be divided into two categories: Components that support the generation and maintenance of the individual tracking images Devices that generate some manner of alert warning, such as an audible signal or a visual signal Floor Components The components addressed in the most detail in this manual can be divided into floor components and control room components. Floor QAS PLC Used to run the QAS Tracking Image Application and AVI/VMS Driver. Encoders Used to send counts or pulses to the Floor QAS Programmable Logic Controller (PLC) to track vehicle movement on the conveyor. The Very High Speed Counter (VHSC) Used to count pulses from the encoders and block transfers the counts to the Floor QAS PLC. AVI Barcode Readers Used to provide bar code label data to the Floor QAS PLC. Photoeye Used to determine if the carrier is empty. 4 of 16

5 Limit Switches Limit switches are used for two reasons: To signal a No Read if data is not received by the time the limit is activated To signal that a carrier is clear of the station and send the job information to the tracking image There are three common types of limit switches used: 1. Physical switches 2. Photoeye 3. A simulated switch using encoder counts PanelView Used to display and input information to and from the Floor QAS PLC. Station Lights Used to announce ALS events to local operators. Restart Pull Cord Used to restart the line after an automatic line stop, bypassing the condition that caused the line to stop. Data Center Components The QAS Workcell (WCC) Houses the SoftLogix engine and the QAS Realtime Configuration Database. The Configuration Database Server Houses the Configuration Database and a copy of the Realtime Database. 5 of 16

6 Summary The QAS system consists of equipment on the plant floor that relates the ID of the job (vehicle, subassembly, or component) to production problems of a specific station. These components are: AVI Reader point to establish the ID of the job as it enters the conveyor. Encoder hardware connected to the conveyor that tracks the position of the job as it moves down the line. A Workcell Controller (WCC) to match vehicle position with configured points. Interlocks between the WCC and the conveyor to stop the line for configured problems signaled by the operator, automated tooling, or PFS. It is the communication of QAS to these systems that forms a total quality management system. 6 of 16

7 Notes: 7 of 16

8 QAS Communication flow The following steps describe the normal communications flow procedure for QAS vehicle sequencing. Step Action 1 The bar code reader will pass the bar code data to the Floor QAS PLC AVI driver. 2 The Floor QAS PLC communicates the bar code data to the AVI supervisor PLC. 3 The AVI supervisor PLC communicates the bar code data to the AVI WCC computer. 4 The AVI WCC computer communicates response data back to the Floor QAS PLC. 5 An encoder mounted on the conveyer provides counts, which are converted to position in feet, to the local Floor QAS PLC. 6 This position and the bar code label for all jobs on a conveyor, which together are called the tracking image, are stored in the local Floor QAS PLC. 7 Each time the conveyor moves 1 foot, the tracking image is sent to the QAS WCC via Ethernet. 8 The QAS WCC transfers bar code and position information to PFCS to be married to tool data and to PFS for sequencing of terminals. 8 of 16

9 Floor QAS PLC Communication Flow Floor QAS PLC QAS Tracking Image Application Distance Traveled Encoder Tracking Image QAS WCC AVI/VMS Driver Vehicle Data Bar Code Label AVI/VMS System QAS WCC Communications Flow QAS WCC SoftLogix5 Engine Floor QAS PLC PFCS PFS Realtime Database PFS Terminal 9 of 16

10 Architecture QAS is an application that utilizes several different types of communication media. The system communicates over Ethernet, DH+, and Remote I/O cabling. The system is set up to allow communication between components on the plant floor and the data center. WAN Computer room Config Db Realtime Db PFS AVI Server PFCS QAS Configuration Database Server QAS Workcell Softlogix Plant Floor Ethernet (TCP/IP) or QAS Floor PLC Terminal server Serial Tool controller RIO AVI Reader Panelview Conveyor C1 Conv segment C1A Encoder Conveyor C1 Conv segment C1B PFS Terminal 10 of 16

11 Tracking Image Introduction A tracking image holds data about each job on a conveyor. The image is held in the Floor QAS PLC or in a PLC, which is closely coupled with the conveyor. Note: The tracking image is per conveyor and is not a plant-wide representation. A job enters the image when it starts on the line. The PLC collects the following information for each job: Job ID Initial position Other attributes of the job on the conveyor: Empty Carrier Not Validated by AVI Parts Buck Skipped Job Out of Sequence Insert Job Unknown Job Manually Entered Duplicate Entry Manually Entered Duplicate As the jobs progress down the conveyor, encoders track the vehicle. The encoder is mounted on the conveyor and provides counts, which are converted to position in feet, to the Floor QAS PLC. The Floor QAS PLC sends the tracking image to QAS. An entire image table is sent to the QAS WCC when the conveyor progresses an increment of 1 foot. Continued on next page 11 of 16

12 Communication The following actions occur each time a vehicle enters a configured station: QAS announces it to PFCS PFCS communicates the information to PFS PFCS communicates the ID of the job from QAS to PFS along with the following information: Conveyor ID Station ID Job ID Position on the line Attributes Sequencing Points Sequencing points are configured places along the conveyor that recognize when a vehicle arrives at that position and announce the ID and other information to PFS and PFCS. This sequences the tool or terminal to the vehicle that just arrived. 12 of 16

13 Types of Stations Introduction A station is a job space on the line where an operation is performed on the job (vehicle, subassembly, or component). A station may start any place on the line and is one job space or less in length. The three types of stations are: Automatic Line Stop (ALS) PFS Sequencing Station Upgrade Station Automatic Line Stop (ALS) These stations contain automated tools. Electronic tool controllers control the operation(s) of these tools. If the controller detects an out of specification condition (for example, a torque gun not turning the required number of times), the following actions occur: Step Action 1 The tool controller sends a message to PFS via PFCS. 2 If the operation failed, PFCS signals the operation failure to the QAS WCC for the vehicle recognized to be at that station. 3 QAS sends a signal to PFS to announce the alarm at the station and signals the alert to the Factory Information System (FIS) and local station light, if present. 4 If the operator at the station cannot get a pass for that vehicle, the line is automatically stopped. FIS and PFS are notified of the line stop. 5 The operator may correct or bypass the failed operation for the line to resume motion and clear the FIS and PFS indications. 6 If the operator bypasses the problem, information is logged into PFS with the details of the vehicle s problem that was recognized at that station. If the operator corrects the problem, it is closed in PFS. 7 Depending on the problem, it may be corrected in an upgrade station before the vehicle reaches the end of that production zone. 13 of 16

14 Types of Stations, Continued PFS Sequencing Station A sequencing station or point uses QAS to track vehicles in station based on location of the vehicle and preset station start points. When a vehicle arrives at the preset station start point, QAS announces it to PFS. PFS then sends this information to the associated PFS Terminal for display. Upgrade Station An upgrade station is a repair station located at the end of a production zone. This station was devised to ensure that in most cases, a vehicle with a repair issue does not leave the zone until it is repaired. In some instances, it is more reasonable to move vehicles to the upgrade station for the repair than to attempt to do the work within the station area. The upgrade station operates as an ALS station, and the problem is reported to the station by PFS. Step Action 1 QAS sends arrival message to PFS for the job in station. 2 PFS checks for any open problems configured for that station. If there are problems, PFS sends a fail message to QAS. If there are none, PFS sends a pass message to QAS. 3 If a fail is received, QAS announces the alarm at the station, acknowledges the alert to PFS, which changes the PFS terminal to indicate the alarm condition, and sends the alarm message to FIS. 4 If the operator at the station cannot get a pass for that vehicle, the line is automatically stopped. 5 The operator may correct or bypass the failed operation for the line to resume motion. 6 Information is logged into PFS with the details of the vehicle s problem that was recognized at that station. Notes: 14 of 16

15 Summary Summary QAS is the plant floor interface for: Vehicle Sequencing Automatic Line Stop Notes: 15 of 16

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