Contractor Accidentally Connects to Remote PLC

Event Year: 2003 Reliability: Confirmed
Country: United States
Industry Type: Chemical

A consulting engineer accidentally connected to and reprogramed an AB PLC several states away, via the corporate VPN/WAN. The engineer had previously been working on the affected PLC at the facility earlier in the week. Due to the PLC programming software design, when the engineer returned to his office he inadvertently reconnected to the last attached PLC (the one in the plant) all along thinking he was working on a test PLC in his office.