MASTER SYLLABUS

2020-2021

A.	Academic Division: Business, Industry, and Technology

B.	Discipline: Industrial Technology, Industrial Maintenance

C.	Course Number and Title: EMMT1540 – Ladder Diagrams

D.	Course Coordinator: Jonathan DeWitt

Assistant Dean: Toni Johnson, PhD

Instructor Information:

Name:	Click here to enter text.

Office Location:	Click here to enter text.

Office Hours:	Click here to enter text.

Phone Number:	Click here to enter text.

E-Mail Address	Click here to enter text.

E.	Credit Hours: 1

Laboratory: 3 hours

F.	Prerequisites: EMMT1010

G.	Syllabus Effective Date: Fall 2020

H.	Textbook(s) Title: None

Workbook(s) and/or Lab Manual: None

J.	Course Description: A study of the practical knowledge required to maintain and troubleshoot industrial control equipment properly by locating and properly identifying the nature and magnitude of a fault or error. This involves the understanding of electrical components, their symbols, and their relationships. Emphasis is placed on reading and understanding elementary ladder logic circuit diagrams based upon electrical standards, and above all else, promoting safety.

K.	College-Wide Learning Outcomes

College-Wide Learning Outcome	Assessments - - How it is met & When it is met
Communication – Written
Communication – Speech
Intercultural Knowledge and Competence
Critical Thinking
Information Literacy
Quantitative Literacy

L.	Course Outcomes and Assessment Methods:

Upon successful completion of this course, the student shall:

Outcomes	Assessments – How it is met & When it is met
Identify control components by their schematic symbols.	Weeks 1-11 – Lab exercises, quizzes, midterm and final.
Identify logic circuits as a Boolean function.	Weeks 1-3 Lab exercises, quizzes, midterm and final.
Install, test and troubleshoot various industrial control circuits using Ladder Diagram schematics.	Weeks 2 – 15 Lab exercises, quizzes, midterm and final.
Classify input devices as to their environmental control function, temperature, pressure, motion, flow, or light.	Weeks 2 – 15 Lab exercises, quizzes, midterm and final.
Identify logical control functions, such as latches, interlocks, timing, counting, or sequential using ladder diagrams.	Weeks 2 – 15 Lab exercises, quizzes, midterm and final.
Describe in detail the types of documentation used on a ladder diagram, such as, contact references, dashed and solid lines, component lettering, page references, and tables.	Weeks 2 – 15 Lab exercises, quizzes, midterm and final.

M.	Topical Timeline (Subject to Change):

TRANSFORMERS

The symbol for a dual-primary, single secondary control transformer.

Connection diagram for a dual-primary, single secondary control transformer to a higher voltage line and to a 120-volt control circuit.

FUSES, DISCONNECT SWITCHES, AND CIRCUIT BREAKERS

The basic fuse construction.

The three different types of fuses and some of their uses.

The four different types of circuit breakers and uses for each.

Why time-delay fuses are used with motor starter circuits.

The voltage and current ratings available for fuses and circuit breakers.

The important factors to consider when selecting protective devices.

The symbols for important protective and disconnecting devices.

What is meant by interrupting capacity.

CONTROL UNITS FOR SWITCHING AND COMMUNICATION

Four types of operators for the push-button switch.

Why different colors are used for push-button switch operators.

The symbols for push-button switch units with:

Flush or extended head.

Mushroom head.

Maintained contact attachment.

Several arrangements available for selector switches.

The symbol for the selector switch.

The symbol for the foot switch.

The advantages of push-to-test pilot lights.

The symbol and detailed circuit for the push-to-test pilot light.

The meaning of the letter in the pilot light.

Simple basic circuits using selector switches.

The use of annunciators to obtain process information.

The use of the LED.

RELAYS

Two main uses for the control relay.

How the control relay is constructed mechanically.

The three published ratings for relays.

Why silver is used in relay contacts.

Several factors involved with relay operation, such as contact bounce, overlap contacts, contact wipe, and split or bifurcated contacts.

The interlock circuit and Why it is used.

The symbol for the relay coil, relay contacts, and on and off time- delay relay contacts.

The difference between inrush and holding current in a relay coil.

How the latching relay operates.

The basic uses for the contactor.

SOLENOIDS

Why it is necessary for the plunger in a solenoid to complete its stroke.

The two important problems to consider in the application of a solenoid.

The application of solenoids to operating valves.

The symbol for the solenoid.

Draw a control circuit showing the energizing of a solenoid through the closing of a relay contact, using a control relay, two push-button switches, and a solenoid.

The difference between sealed current and inrush current in a solenoid.

MOTION CONTROL

The three basic classes of limit switches.

Where rotating-cam limit switches are used.

Terms relative to limit switches:

Operating force.

Release force.

Pretravel or trip travel.

Overtravel.

Differential travel.

The proximity limit switch and How it is used.

Several methods for achieving proximity switching.

How the vane limit switch operates.

The limit switch symbols for four different conditions.

Draw an electrical operating circuit showing how the operation of a normally closed limit switch contact can be used to deenergize a solenoid, using two push-button switches, a normally closed limit switch contact, a relay, and a solenoid.

The 4 types of photoelectric transducers.

PRESSURE CONTROL

Terms used with pressure switches.

Tolerance in a pressure switch.

Four types of pressure switches.

How the piston-type pressure switch operates.

The operation of the diaphragm pressure switch.

How the pressure transducer operates.

The normally open and normally closed pressure switch symbols.

Draw an electrical control circuit showing how a normally closed pressure switch contact can be used to deenergize the circuit.

TEMPERATURE CONTROL

How the thermocouple, thermistor, and resistance unit obtain temperature information that can be used in a control circuit.

Name two types of temperature switches or thermostats and how each operates.

How a temperature switch contact can be used in an electrical control circuit to prevent the operation of the circuit unless the temperature of the part being sensed is at or above a preset temperature.

TIME and COUNT CONTROL

The differences between a timer and a time-delay relay.

Where the timer has a definite use.

Three major types of timers

The difference between the on-delay and off-delay timer operation.

The arrangement of the contacts in a reset-type timer under the conditions of reset, timing, and timed out.

The function of the timer sequence symbol above each timer contact.

The operation of the repeat-cycle timer.

Some of the design features of the solid-state timers.

CONTROL CIRCUITS

How all complete control circuits progress through three basic areas: information or input, decision or logic, and output or work.

Draw a Bar chart sequence for an electrical control circuit.

How various electrical components are used to gather information from a machine system.

How electrical components are used to make a decision as to how the gathered information is to be used.

How the decision affects the output or work the machine is to accomplish.

Simple electrical circuits from a given set of requirements.

MOTOR STARTERS

The difference between a contactor and a motor starter.

Why overload relays are used on motor starters.

How the normally closed contact in the overload relay is connected into the motor starter control circuit.

Why both mechanical and electrical interlocks are used on the reversing motor starter.

Draw a single phase reversing motor circuit.

GENERAL

Categorizing a given electro-mechanical control device as:

Input or conditional.

Output or load.

Miscellaneous or support .

How to use contact cross references in conjunction with rung numbering to locate both normally open and normally closed contacts associated with the output device of a given ladder diagram rung.

How to locate contacts in other rungs that are mechanically linked to a contact located in a given rung of ladder logic.

How to use conductor numbers from a given ladder diagram to locate the voltage test points on the terminal strip of a relay control panel.

The on/off status of the output or load device in any rung of a ladder diagram when given the on/off status of the input or conditional devices in that rung.

The operation of basic rung logic circuits such as "AND" logic, "OR" logic, "NOT" logic, sealing or latching contacts and lockout contacts in a given ladder diagram.

The control sequence of a relay control system when given the status of the input or conditional devices and a ladder diagram of that system.

Safe use of a voltage tester to verify the on/off status of any device in any rung of a given relay control system when given its corresponding ladder diagram

Safe use of a continuity tester or Ohmmeter to verify that a suspected control device has failed.

How to safely troubleshoot and repair any relay control system when given the ladder diagram, the point at which the control sequence failed, a voltage tester, a continuity tester and proper replacement devices(s).

N.	Course Assignments:

Homework: Selected problems and questions from weekly reading assignments must be completed.

Labs: Various self-paced and computer monitored labs administered in the IST lab.

Quizzes: Quizzes will be administered online via LMS.

Midterm: The midterm exam will be administered during week 8.

Final: There will be a comprehensive final at the end of the semester.

O.	Recommended Grading Scale:

NUMERIC	GRADE	POINTS	DEFINITION
93–100	A	4.00	Superior
90–92	A-	3.67	Superior
87–89	B+	3.33	Above Average
83–86	B	3.00	Above Average
80–82	B-	2.67	Above Average
77–79	C+	2.33	Average
73–76	C	2.00	Average
70-72	C-	1.67	Below Average
67–69	D+	1.33	Below Average
63-66	D	1.00	Below Average
60-62	D-	0.67	Poor
00-59	F	0.00	Failure

P.	Grading and Testing Guidelines:

Click here to enter text.

Q.	Examination Policy:

Click here to enter text.

R.	Class Attendance and Homework Make-Up Policy:

Click here to enter text.

S.	Classroom Expectations:

Click here to enter text.

T.	College Procedures/Policies:

Important information regarding College Procedures and Policies can be found on the syllabus supplement located at

http://catalog.ncstatecollege.edu/mime/download.pdf?catoid=5&ftype=2&foid=3