1.  Introduction

The main objective of this assignment is to design a fully automated system to concentrate bacteria from tap water through a filter as shown in Figure 1. It must also be capable of controlling the initial volume to be concentrated and the opening and closing of valves in relation to the application.

You do not need to build the system; this will be a paper exercise where you will gather information about suitable devices (sensors, datasheets, etc.)

Figure 1: Schematic representation of the system set-up (V denotes the valves and P the pump)

2.  System Description

There are three design stages:

a)    Filtration: From the tap water to a sample tank to the filter via (Valves: V7, V1, V3 and V5) as shown in Figure 1. So, clean water will be drained and any particles (bacterial species) will remain inside the filter.

b)    Backflushing: a second stage is required to retrieve these particles for further analysis via (Valves: V2, V4 and V6).

c)    RS-232 Serial Communication: In the final stage, the proposed system should also be able to communicate with the PC.

Initial stage is necessary to verify the level of the elution solution which is needed to clean the filter and also verify that all valves are closed prior to operation. Then, the system starts the filtration stage from tap water for a predefined volume which is set by the user. Once the filtration is finished, the elution backflushing stage will start to clean the filter as shown in the schematic Figure 1. Finally, the system should also able to communicate with PC via RS-232 serial Communication. Then, PC will be informed the current status of the system and instructs the next course of action.

3.   Coursework Description

Design the instrumentation system and simulate using the Proteus Software

·         The pressure transducer should be simulated using the analogue input on the development system.

·         Use a standard 2 x 16 or 4 x 20 character display to show messages as suitable to  the system

·         Your system should provide the 4 bits to directly drive the pump and the valves (Simulated as a stepper motor up and down or LEDs ON/Off). 

·         Develop a solution to be written in C codes and fully commented.

·         Develop a test strategy to ensure the program meets fully with the design specification

·         Make reasonable assumptions where specification is not clear

·         Where you have ‘added’ value to the design, due credit will be given

4.  Assessment Criteria

You should present a report on the development of your solution with certain key elements as follows:

a)     Clear description of the methodology you are using to implement the system. A flow chart or Pseudo English or similar description of the way in which you are solving the problem.

b)    A clear well documented program which follows a logical process and is based on the solution in Figure 1.

c)    An evaluation of the design in terms of areas of weakness and possible improvements which could be built in.

The assessment will be marked as follows: