The model incorporates the basic elements of a monitoring and control system:
Each gate has two LIMIT SWITCHES which act as input elements, telling the system whether the gate is closed (CL) or fully open (FO).
The indicator elements are INDICATOR LIGHTS, which tell the operator the current state of the system.
The controls are PUSHBUTTONS which let an operator tell the system to move gates or change the status of the shipping bin. The current shipping bin status is displayed at the top of the bin.
The output elements, not shown, power the electric motors which move the gates.
The logic element, also not shown, is a RELAY which forces the bin gate closed unless certain conditions are satisfied. When the bin is in HOLD status, the relay keeps the bin gate shut. When the bin is in SHIP status, the bin gate is forced closed if any grain can flow back to the house. When the bin is in REJECT status, the bin gate is forced closed if any grain can flow to the ship.
The monitoring and control system shown is properly wired. The
indicator lights show the true positions of the gates, and the
relay removes the gate's permission to open at the right times.
You can operate the model and move it around.
Next Page: Alternative Correct Indicator Wiring