Homework Unit 2
The main program in PLC is located in file 2. Subroutines are located in files 3-25.
Describe the difference between a latched (retentive) output and a non-retentive output.
Retentive output instructions are used
1. PLCs were originally developed as replacements for _.
2. Modifying relay-type control circuits usually involves _.
3. The basic difference between a PLC and a relay control panel is that _.
4. The phases of the program scan, in corre
Homework Week 4
1. Describe how an Up Counter works in conjunction with a Down Counter.
For example, if you were using a counter for an assembly line of product that
is being boxed for shipment. One would obviously use an UP c
Homework Week 1
1) Write a definition of a programmable logic controller.
A PLC is a programmable computer that varies in size but is used in automation
for industrial processes like conveyors, amusement rides and other mach
1. What does the term fence mean relative to the MCR instruction?
Fence is the area formed by multiple MCR instructions in the program.
2. What is the function of the second MCR instruction in a control zone?
To define the end of the area.
5. What is the
Homework Week 3
1. Describe a TON timer.
Timer ON Delay turns on an output after a timer has been on for a specific
TON timer starts to accumulate time when rung becomes true.
2. Describe a TOF timer.
Timer OFF Delay t
Programmable Logic Controllers
Homework Week 9
Homework p.580 #s 4,6,7,9,17
4. Describe the operation of the AND, OR, and XOR instructions.
The AND operation simply means all of the inputs must be ON for the output to
be ON; it's analogous