Patent ID: 8752269

Claim:
An interlocking system for connecting a programmable module and an automation controller of an industrial control and automation system, the interlocking system comprising: a key comprising a shaft with a head on a first distal end of the shaft and a first attachment feature cantilevered from a second distal end of the shaft; a first keyhole in a cover of the programmable module, wherein the first keyhole is configured to enable the head to pass upwardly there through; a second keyhole in a cover of the automation controller, wherein the second keyhole is configured to enable the first attachment feature to slide downwardly there through such that axial rotation of the shaft causes the first attachment feature to become misaligned with the second keyhole and abut a lower surface of the cover of the automation controller such that disengagement of the key from the second keyhole is resisted; and a second attachment feature on the lower surface of the cover of the automation controller, wherein the second attachment feature is configured to engage with the first attachment feature when the first attachment feature is rotated about an axis of the shaft and the engagement between the first and second attachment features maintains the first attachment feature in misalignment with the second keyhole.