Application Scenarios

A automotive parts manufacturer in the Midwest needed to integrate a legacy barcode verification station into its SLC 5/03 control system. The barcode reader output ASCII strings over RS-232, but the existing SLC processor had no spare communication port capable of parsing the variable-length data stream at production speed. The integration team installed an Allen-Bradley 1746-BAS in the expansion chassis and wrote a short BASIC program that used CALL 22 to read incoming barcode data from PRT2 into the module’s M1 file, then triggered a handshake bit that the SLC ladder logic monitored .

After commissioning, the Allen-Bradley 1746-BAS successfully captured every barcode scan, passed the four-character symbol and carriage return trailer to the SLC processor, and enabled automatic rejection of mismatched parts. The production line’s verification accuracy improved from manual spot-checking to 100% inspection without requiring a controller upgrade or network reconfiguration. According to the controls engineer, the Allen-Bradley 1746-BAS‘s ability to run BASIC code independently of the SLC scan cycle was the key enabler, as it freed the main processor from the timing-sensitive task of character-by-character serial parsing .

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