I found in a box, at the school were I teach, the Fischertechnik kits 96785 “punching machine” and 536630 “vacuum gripper” and, as they function by 24 Vdc, I thought of building a didactic panel showing PLC programming and interfacing.
While the punching machine doesn’t pose problems, the 3 encoder motors of the vacuum gripper are not that easy to interface and control with the PLC, so that low end PLC can’t handle them. But S7 1200 isn’t low and its first 6 inputs can command encoder motors like these and better.
To use all the functionalities and degrees of freedom of the robotic arm, I decided to put the work piece, to be handled, on a platform, where the robotic arm take it “sucking it” by a vacuum sucker activated by a compressor and a valve. The arm then moves it on the conveyor belt where the work piece is “punched” (only touched really) by an up-down moving block. After this the work piece returns at the beginning of the conveyor belt where the arm takes and move it again on the platform. This is the basic cycle, that the machine can repeat until a problem arises or the watchers are fed up !
The machine’s behavior is controlled by an industrial keypad, complete with light and emergency button to stop everything.
The cabling has been made interposing Weidmuller clamps between S7 and the inputs / outputs, so another PLC or others electronics can be added to the panel.
Any suggestions ?
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