RDU Data Collection System Overview. System Overview. * The RDU data system is, primarily, an RF-Tag-based system. * All process information and test results are written to the RF-Tag * The data collection PC, using a database, collects all test results as well . System Overview.
* The RDU data system is, primarily, an RF-Tag-based system.
* All process information and test results are written to the RF-Tag
* The data collection PC, using a database, collects all test results as well
* The part's serial number and its status (pass, fail, not tested) is read from the RF-Tag
* If process data (gaging information, shim call, etc) from upstream stations is needed, it is read from the RF-Tag
* After the machine completes its work, all results are written to the RF-Tag and to the central database
Data is guaranteed to be recorded on the RF-Tag as well as in the database.
Each individual data path (RF or database) is trustworthy and automatically verified.
Database transactions use a checksum to verify that data in the database matches that in the station.
* The station PLC generates a checksum before it sends its data.
* The database generates a matching checksum that is transmitted back to the station PLC after data collection.
* The PLC only accepts the transaction as complete if the two checksums match.
RF-Tag reads and writes always include verification.
* Two RF-Tag read operations are always performed together, and the two sets of data are compared to one another. The read operation is only considered successful if the two sets of data match.
* After an RF-Tag write is completed, the data is read back from the RF-Tag and then compared to the expected value. If there is any mismatch, the station automatically repeats the write until it succeeds.
A simple, flexible, reliable tool (written in VB.NET) is used to collect data from the Main PLC, and then send that data to the database.
Test results data is stored in a simple, event-based format. Each completed station cycle generates one basic record.
A final summary of the most recent basic records (one per station) is created for each part at the end of the assembly process.
The Reports Wizard constructs summaries of this data, depending on the purpose of the report.
The line has complete data redundancy because data is stored to both the RF-Tag and the database.
If the database fails, production can immediately resume using the RF-Tag system. No in-production data is lost (the line does not need to be cleared). At the end of the process, data will be read from the RF-Tag, then stored to an alternate PC.