Draw a ladder diagram for each exercise BY HAND. Explain how you would design the system, detailing your approach and rationale. Explain each rung of the ladder diagram clearly, ensuring that you cover the function and purpose of each part. EXERCISE 1 – ANNUNCIATOR In industry, plant conditions are monitored and, if there are problems, it is necessary to have some way of indicating such problems. An indicator system of this type is called an Annunciator. A typical alarm system uses the following sequence to indicate a plant alarm condition to an operator. (i) System healthy – no indication. (ii) System in alarm – a flashing Amber light and audible alarm. FIGURE 1 shows the graphics simulation of the alarm system. 1. If the operator presses the ACCEPT button when the plant is in alarm (ii above), the audible alarm stops and the flashing Amber light changes to permanently ‘ON’. 2. If the plant drops out of the alarm condition before the ACCEPT button is pressed, the panel will show a flashing Green light. The Audible alarm and Amber light will go ‘OFF’. 3. If the ACCEPT button was pressed when the plant is healthy as in 2 above, the flashing Green light will go ‘OFF’. 4. There should be a LAMP TEST button which, when pressed, will light all lamps and sound the audible alarm. 5. Write a program that will operate the Alarm Simulation, using the following inputs and outputs and whatever Timers and Flags are required. IP0 = Plant alarm condition OP0 = Amber Lamp IP1 = Operator accept button IP2 = Lamp test OP1 = Green Lamp OP2 = Audible Alarm EXERCISE 2 – CAR PARK FIG. 2 Car Park Simulation Consider the above diagram, FIGURE 2, of the car park. The object of this assignment is to write a program to operate the barriers to allow the cars in and out. As you can see there is a box in which there are two condition lights for when the car park is full, and when there are spaces. The entrance to the car park is on the left hand side. When a car drives into the car park there is a sensor that detects the car and this should cause the barrier to be opened to allow the car in. On the right hand side is the exit. When a car leaves the car park it will activate a sensor inside the park to open the exit barrier. Both the entry and exit barriers will need to be in the up position long enough to allow the cars to enter or leave the car park. The inputs and outputs are listed as follows: IP0 = Entry Sensor IP1 = Exit Sensor OP0 = Entry Barrier OP1 = Exit Barrier OP2 = Full Light OP3 = Spaces Light When writing the program it is necessary to observe the following conditions. When the car park is not full the Spaces light should be ‘ON’. When the car park is full the Full light should be ‘ON’. As a car enters or leaves the car park the entry and exit barriers have to be held in the up position long enough to allow the cars to pass under the barriers.