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: E2_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 #02 Dropbox via Online@DSC.

Problem No. 1:

Design a PLC ladder logic program to control the operation of an alarm system consisting of three (3) Horns (HORN_1, HORN_2, and HORN_3) and four (4) normally open proximity sensors (INPUT_1, INPUT_2, INPUT_3, and INPUT_4) using the following sequence:

- HORN_1 and only HORN_1 must be energized if any two and just two of the sensors are activated.
- HORN_2 and only HORN_2 must be energized if any three and just three of the sensors are activated.
- HORN_3 and only HORN_3 must be energized if all four sensors are activated.
- Notice that no two Horns can be activated at the same time.
- Do not use latch and unlatch instructions.
- Assign sequential addresses to the input and output devices starting from bit 1.

Problem No. 2:

Design a PLC ladder logic program for the following temperature control system to maintain a room between 20°C and 30°C using a combination of an AC unit, a HEATER, four (4) normally open thermostats (T_20, T_22, T_28, and T_30), and a MASTER normally open switch using the following sequence:

- If the temperature reaches 30°C, which activates T_30, the AC must be energized and kept energized until the temperature decreases to 28°C, which deactivates T_28.
- If the temperature reaches 20°C, which deactivates T_20, the HEATER must be energized and kept energized until the temperature increases to 22°C, which activates T_22.
- The MASTER switch must be turned on for both the AC and HEATER to operate.
- Use Latch and Unlatch instructions for this control process.
- Assign sequential addresses to the input and output devices starting from bit 0.

Problem No. 3:

Design a PLC ladder logic program to control the operation of a forward-reverse dual motion motor (programmed as two separate motors: FORWARD and REVERSE) with three (3) normally open momentary contact pushbuttons (FOR_START, REV_START, and STOP), as well as two (2) indicator pilot lights (FOR_LIGHT and REV_LIGHT) using the following sequence:

- The FORWARD motor must run and stay in motion when the FOR_START
button is momentarily activated. FOR_LIGHT must be energized.
- The REVERSE motor must run and stay in motion when the REV_START
button is momentarily activated. REV_LIGHT must be energized.
- The FORWARD and REVERSE motors cannot operate simultaneously.
- Both the FORWARD and REVERSE motors must stop when the STOP button is momentarily activated. Both the FOR_LIGHT and REV_LIGHT lights must be de-energized.
- Do not use latch and unlatch instructions.
- Assign sequential addresses to the input and output devices starting from bit 0.