Course Objectives Assessed

1. Understand, use and create system specification documents

4. Program a typical PLC to perform a specific task using FBD and ladder code 

PLC Programming

Your task is to program the water supply buffer system for a process that requires a steady flow of water available for cooling.

The details of the system are given below. The code is to be programmed in Ladder language using the template file provided. The preferred version of software is ZelioSoft 2 v 5.3.1

Hardware

The Zelio relay used is the SR3B262BD with an digital I/O expansion module SR3XT101BD. This is pre-configured in the provided template.

System Operation

Refer to the provided Piping and Instrumentation Diagram (Drawing ELE1301-S1-21-P&ID) to support this explanation.

There are two tanks, TK001 and TK002. The two tanks work together to provide a steady flow of water for cooling to a separate process.

There are two operations that may occur in a tank: fill and supply.

When the system is first turned on, both tanks will fill. The system will then indicate to the following process that it is ready to supply water by activating the “Water Supply OK” output.

When a “Process Call” input is received, tank 1 will supply the water to the process until the low level switch (LSL001) in tank 1 is activated. At this point, tank 2 will take over and supply water to the process while tank 1 fills until it reaches the high level switch (LSH001). This process continues, with one tank filling as the other supplies and then swapping over.

The tanks are filled through valves V001 and V002.

The tanks supply water through valves V003 and V004.

V005 will be opened when either V003 or V004 are supplying water.

The fill or supply functions will only operate when the “On” switch is activated.

In addition, the supply function will only operate when the “Process Call” input is activated.

Both tanks have high, high high, low and low low level sensors. The high and low level sensors should be used to swap between fill and supply functions. The high high and low low level sensors should be used to detect alarm conditions.

All valves have position feedback and the program should include alarm logic.

There is a flow switch after V005, which will alarm if there is no flow for 5 seconds when V005 is open.

All inputs to be debounced for a suitable time.

All alarms are to be latched.

There is an alarm output to indicate alarm states, and an alarm reset pushbutton to clear alarms. There is another light which indicates when the system has been turned on.

Report:

You must submit a report that meets the following minimum objectives:

 An overview of the operation of the system.

 Documentation of assumptions or clarifications around the task (if any).

 A brief Functional Specification. This means that for each item (that is part of the PLC system) in the plant, you will provide a short description of the required operation, impact on other equipment and any alarms related to that device.

 A timing chart showing the normal operation of the plant from being turned on to supplying water from tank 1, then tank 2 and switching back to tank 1.

 Description and documentation of the code structure, along with any variables, timers and counters used.

 Screen shots of two cases showing the code window and supervision window (with I/O visible): 

(i) Tank 2 supplying water while Tank 1 fills, and

(ii) V003 has failed to open while Tank 1 was supplying water.

 Documentation of the testing process undertaken and the full results of the testing process. The presentation of this data is up to you but it should be thorough and logical.

Design-Assignment-2-PID

Design-Assignment-2-Template-UPDATED.zm2