PLC History & Manufacturers
This was the first PLC released.
What is Modicon 084?
Digital inputs have signals that are represented by these two values.
What are 0 or 1?
This drawing shows the physical location and connections of electrical components in a circuit.
What is a wiring diagram?
These switches are activated by a machine operator or technician to cause an action at a desired time.
What are manual switches?
This system uses G-code to control operation.
What is CNC?
This company created the PLC-5, SLC 500, and ControlLogix product lines.
What is Allen-Bradley?
This PLC instruction looks for a 1 in the bit box.
What is XIC?
These diagrams are used for electrical control circuits.
What are ladder logic diagrams?
These switches are typically push buttons that return to their original position when released.
What are momentary switches?
These devices perform multiple timing functions and may control outputs like a limited PLC system.
What are smart relays?
This was Allen-Bradley's first PLC released.
What is PDQ-11?
This instruction contains a DN (done) bit.
What is a TON timer?
A dashed line in a wiring diagram represents this.
What is a mechanical connection?
These spring-loaded push buttons close contacts while the button is held down and are commonly used as start buttons.
What is a normally open push button?
This type of module includes communication, PID, safety, and combination modules.
What are specialty modules?
This company created the S5, Simatic S7, and Step 7 PLC systems.
What is Siemens?
This light indicates the processor is scanning the program normally when solidly lit.
What is the RUN light?
In wiring diagrams, crossing lines are not connected unless this symbol is present.
What is a dot at the intersection?
These switches are often used as emergency stop switches and are also called mushroom-head switches.
What are palm-operated switches?
These devices allow operators to interact with a graphical interface and may include keyboard inputs.
What are HMIs?
This company is known for developing the PLC-5, SLC 500, and ControlLogix lines.
What is Allen-Bradley?
This light indicates that the processor is running normally when solidly lit.
What is the OK light?
These wiring diagram lines, labeled L1 and L2, are drawn thicker than horizontal lines.
What are the vertical power lines?
These switches allow an operator to activate a device when their hands are busy performing another task.
What are foot switches?
These systems differ from contactors because they include overload modules.
What are motor starters?