Hardware
This is the "brain" of the PLC where logic is processed.
The processor.
In this step, the PLC checks which buttons or sensors are pressed.
Input Scan
These are the horizontal lines that hold code instructions.
Rungs
A simple ON or OFF signal, like a standard light switch.
Discrete
This instruction is used to delay an action, like waiting 5 seconds before a belt starts.
TON, on delay
The part of the PLC connects it to real-world devices.
I/O Modules.
In this step, the PLC reads the ladder program from left to right, top to bottom.
Program Scan
A contact that only lets "power" through when it is activated (pushed).
N/O, XIC
A variable signal that can represent a range, like 0 to 100 degrees.
Analog
This instruction tracks how many items have passed a sensor.
Counter(CTU, CTD)
This component converts standard high-voltage power into the low DC voltage the PLC needs.
Power Supply
During this step of the scan, the processer performs diagnostic checks.
Housekeeping
A contact that stays "closed" (on) until it is activated.
N/C, XIO
A sensor that detects if a box is present or not is this type of input.
Discrete
This is the "goal" number you type into a timer or counter.
Preset
This is the laptop or PC used to write the program and download it.
Programming Device.
This step is when the PLC finally sends power to the motors or lights.
Output scan
The symbol at the far right of a rung that represents the device you are controlling.
Output(OTE)
A sensor that tells you exactly how much liquid is in a tank is this type of signal.
Analog
This is the "live" number showing the current time or count as it happens.
This is the physical rack or rail that allows all the modules to talk to the CPU.
Backplane
During operation, a PLC performs a series of steps continuously. This is called the _______.
The scan cycle
Placing two contacts in parallel creates what type of logic gate?
OR gate
This type of signal is usually measured in voltage (0-10V) or current (4-20mA).
Analog signal
You must use this instruction to move a counter or timer back to zero.
reset instruction(RES)