DAYTONA STATE COLLEGE
SCHOOL OF ENGINEERING TECHNOLOGY
EST 3543: Programmable Logic Applications and Device Integration
EXAM #3 (Open books and notes. 120 minutes)
Instructions:
The three (3) problems in the exam are to be programmed directly using RSLogix. You
must create a new program file for each problem and setup the proper controller type.
Identify each problem with a program file using the following format: E3_x_FML.RSS.
Where x is the problem number and FML are your first, middle, and last name initials.
Enter the ladder logic on the corresponding window. All symbols must be specified and a
description must be added stating the type of device with its normal state (NO, NC).
Upload the three (3) .RSS files and submit them through the Exam #03 Dropbox via
Online@DSC.
Problem No. 1: (35 pts.)
Design a PLC ladder logic program to control the operation of a conveyor-storage system
using the following sequence:
- Program a count-up to keep track of the parts brought into the storage room by
the CONVEYOR_IN and detected with a PROXIMITY_IN sensor.
- Program a count-down to keep track of the parts taken out of the storage room
by the CONVEYOR_OUT and detected with a PROXIMITY_OUT sensor.
- Both conveyor motors are operated by one START/STOP seal-in pushbutton
station.
- A GREEN light must be on if the part count in the storage room is equal to
zero (0).
- A YELLOW light must be on if the part count in the storage room is between
one (1) and ten (10) (inclusive).
- A RED light must flash on and off in periods of 0.5 seconds if the part count
in the storage room is greater than ten (10).
- A RESET pushbutton is used to reset the count.
- Program CONVEYOR_IN and CONVEYOR_OUT using bits 0 and 1 of the
output module.
- Program the GREEN, YELLOW, and RED lights using bits 2, 3, and 4 of
the output module.
- Program the START and STOP buttons as normally open in bits 0 and 1 of
the input module.
- Program PROXIMITY_IN and PROXIMITY_OUT using bits 2 and 3 of
the input module.
- Program the RESET pushbutton using bit 4 of the input module.
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Problem No. 2: (35 pts.)
Design a PLC ladder logic program to control the operation of an automatic mixing
process using the following sequence:
- A solenoid valve, VALVE_IN, automatically allows fluid in the mixing tank
3 seconds after a level switch, LEVEL_EMPTY, detects when the tank is
empty.
- VALVE_IN is automatically de-energized as soon as a level switch,
LEVEL_FULL, detects when the tank is full.
- A mixer MOTOR is automatically energized for 10 seconds after the tank is
full.
- After the 10-second mixing period the mixer MOTOR is automatically shut
down.
- A second solenoid valve, VALVE_OUT, is energized to drain the tank
immediately after the MOTOR shuts down.
- VALVE_OUT is automatically de-energized as soon as the level switch,
LEVEL_EMPTY, detects when the tank is empty. The filling process must
start over at this point.
- A master switch, ON_OFF, is used to manually turn off the solenoid valves
and the mixer.
- Hint: Latch/Unlatch both valves and motor with intermediate bits.
- Program ON_OFF on bit 0 of the input module.
- Program LEVEL_EMPTY on bit 1 of the input module.
- Program LEVEL_FULL on bit 2 of the input module.
- Program MOTOR on bit 0 of the output module.
- Program VALVE_IN on bit 1 of the output module.
- Program VALVE_OUT on bit 2 of the output module.
Problem No. 3: (30 pts.)
Design a PLC ladder logic program to control the operation of an alarm system using the
following sequence:
- An ALARM must be energized and stay energized (latched) when a limit
SWITCH is activated once or when a motion SENSOR is activated three (3)
times within a space of 30 seconds.
- The ALARM can only be de-energized (unlatched) by pushing a hidden
normally-open momentary-contact BUTTON.
- Hint: latch the timer with a sensor activation and use a count-up instruction to
count the number of sensor activations. Reset the count and unlatch the timer
if the timer is done.
- Program SWITCH, SENSOR, and BUTTON using bits 0, 1, and 2 of the
input module respectively.
- Program ALARM using bit 0 of the output module.
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