As shown in the illustrated ladder diagram for a programmable logic controller used to control a motor, what statement is true? See illustration EL-0237.
• PLC ladder logic symbols: vertical power rails, horizontal rungs, and the difference between contacts and coils (loads) • How input devices (like pushbuttons and switches) are drawn compared to output devices (like motors and lamps) • Normally-open/closed contacts vs. output coils in a control circuit
• On each rung, identify which symbols represent something that actually consumes power (motor, lamp) and which represent control contacts • Decide which numbered items are field devices wired into PLC inputs, and which are controlled by the PLC outputs • Compare how items 1, 2, 4, 5, and 7 are drawn – do they look more like switches/contacts or loads/coils?
• Make sure you can point to every output coil/load symbol on the diagram before choosing any answer • Verify that input contacts (like Start/Stop) are on the left side of rungs, controlling current to the right-side loads • Check that items labeled as "motor output contacts" are contacts controlled BY a PLC output, not the output loads themselves
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