The following is the given ladder diagram for a system with manual controls:
(a) It is given that 8-point I/O cards are used. Here, use one-slot addressing; it means there are only 8 points for input in group 0 and 8 points for output in group 1.
Therefore, the addressing bits will vary from 00-07 for both input and output devices.
The following ladder indicate the required inputs:
The following ladder indicate the required outputs:
(b) In figure 1, when the power supply is provided, the green on the third will be on as it is connected to a normally closed switch. When start-1 button is pushed, the coil relay (CR1) will get energized and the switches CR1-1, CR1-2 and CR1-3 will change their state. CR1-1 and CR1-3 will be closed and CR1-2 will be opened due to which green light will be off.
When CR1-3 and float switch closed simultaneously, CR2 will get energized and CR2-1 and CR2-2 will be closed. CR2-1 will start the motor A and CR2-2 will switch on the red light on rung 10.
When start-2 is pressed, CR3 will get energized, which in turn will close CR3-1, CR3-2 and CR3-3. CR3-2 and CR3-3 will turn on the motor B and red on rung 11, respectively.
The following is the PLC ladder diagram showing the addresses for all devices: