Analysis of Programmable Logic Controller Programming Techniques

This report provides a comprehensive analysis of Programmable Logic Controller (PLC) programming techniques, evaluating methods such as flowcharts, truth tables, and logic function diagrams. It discusses the advantages and disadvantages of each method, using a fire alarm system implementation as a case study to determine the most efficient approach. The report also explores the principles of online and offline programming with PLC, highlighting their respective advantages and disadvantages, and delves into debugging techniques like Recurrent Neural Networks (RNN), data simplification, divide and conquer, and process slowing, assessing their usefulness and limitations. The conclusion emphasizes the cost-effectiveness, customizability, and robust nature of PLC programming, making it a valuable tool in automation.

Running header: PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
Programmable Logical Controller Programming
Name of the Student
Name of the University
Author Note

1
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
Task 2:
Flowchart Method:
Advantages: PLC programming requires block diagrams to explain the functionalities
and flowchart can be very much effective in serving that purpose. Flowcharts are extremely
perceptive of the logically descriptive nature of PLCs and it is also a simple way of designing a
complex logic (Berger et al. 2014). Flowchart is the form that can be understood by anyone and
thus communication of the logic becomes simpler. Documenting control sequences becomes
easier for engineers when explained via flowcharts. Cost and time management are optimized by
means of effective problem analysis through flowcharts. It serves as the blueprint for the entire
system providing efficient coding (Netto and Bagri 2013). Flowchart also contributes greatly in
identifying problems and debugging them.
Disadvantages: A few complicated areas of the programs cannot be efficiently
documented by flowcharts as it becomes clumsy to establish coherence. Adding the
modifications to the flowchart is very difficult, as it requires the flowchart to be drawn over
again. Reproduction becomes quite the hindrance, as flowcharts are not typed.
Truth Tables:
Advantages: The main advantage of using truth table is that it provides a mechanical
viewpoint on the logical controller system and engineers do not have to consume time thinking
about creative ways to deliver logic.
Disadvantages: The primary disadvantage of truth tables is that it covers very less of
the entire programming system. The result provided with the help of truth tables are sometimes

2
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
very unpractical and fitting the entire logic in a truth table is extremely disturbing. Explaining
simple statements of programs is very difficult in case of truth tables.
Logic Function Diagrams:
Advantages: Use of logic function diagrams is extremely beneficial in documenting
logical controllers. Logical diagrams are efficient in identifying and documenting noises. Signal
representation is easy with logical diagrams. In PLCs, the use of logic circuits is obvious and to
explain the functionalities of the circuits, logic function diagrams are inevitable.
Disadvantages: The biggest disadvantage with logic function diagrams is that the
diagram consists of networks and implementing complex logic using logic diagram becomes
cumbersome. With complex logic, the diagram becomes too complicated to understand and
hence, working with such documentation is inefficient.
Evaluation of the Methods:
Among the PLC programming methods mentioned above, an evaluation should be
performed examining the better method. If a fire alarm is implemented by means of a logic
controller, then various steps need to be documented, such as the critical point when the alarm is
set off, recording temperature, detecting increase in temperature and setting off when the critical
point is hit (Huyck et al. 2014). All of these steps are required to be documented well and
flowchart is the method that can encompass all the possible logic behind the working principle of
a fire alarm and also it will be easier to understand for the engineers, which contributes to
productivity. Truth Tables can only cover the results of the overall process and function
diagrams will only document the working circuits behind the controller, not all the necessary

3
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
steps. Therefore, it can be said that flowchart is better and efficient method for PLC
programming.
Task 3:
Offline and Online Programming with PLC:
As the name suggests, offline programming cannot facilitate the services and advantages
provided by the internet and therefore, coding offline will lead to a download of the program in
the PLC (Joshi et al. 2016). Programs serving the stand-alone machines need to be programmed
offline. Existing stand-alone programs can be modified by means of offline programming.
Online programming can serve as the editing process of existing programs which may
already be running (Huyck et al. 2014). It involves greater risk of harming systems and
comprising the safety conditions.
Advantages and Disadvantages of Offline Programming:
 The biggest advantage of offline programming is that it is safe as the system is
allocated a considerable amount of time to prepare for changes.
 The disadvantage of offline programming is that it is time consuming, as the
PLCs pause the existing programs to get the new programs downloaded.
 It causes the machine to sit idle.
 It is more error prone as the code is not tested.
Advantages and Disadvantages of Online Programming:
 The major advantage with online programming is that it does not keep the
existing program out of order to make alterations. It involves dynamic coding.

4
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
 The disadvantage with online programming is that while the changes take effect,
it might cause the system to be damaged.
Task 4:
Debugging:
The methods used to debug the PLC programs are Recurrent Neural Network (RNR),
simplification of complex data, divide and conquer and slowing down of the process.
Usefulness:
 RNR helps in analysis of the dynamic programming or online programming
through feedforward nets.
 Using simplification will help in digitizing the analog data and this digital form
will be easier to process and handle.
 Divide and conquer will help by providing effective solution to complex
problems. It also ensures efficient algorithms to solve the bugs in a PLC program.
 When data is fed to the processor too fast then the algorithm might not work
properly and in this case, slowing down the clock rate or the amount of data flow
can help.
Limitations:
 The RNNs basically learn by evaluating programs which are long in sequence and
there are usually errors in evaluation process (Zaremba, Sutskever and Vinyals
2014). Thus, it is often experienced that the networks produce results which are
unexpected.

5
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
 Digitization of the analog data may not be needed every time and hence, this
debugging technique has a very little scope in the debugging process.
 Divide and conquer is the method of devising efficient algorithms where the
problem requires division into equal sets. However, PLC programs do not need
this approach in every cases (Basile, Chiacchio and Gerbasio 2013). Divide and
conquer does not offer a good debugging approach as it requires repetition of the
same code segment and it can result in excessive time consumption.
 Slowing of the data and clock rates can prove to be inefficient as overflow of data
feeding is not a problem that a PLC program faces too often. This can be rendered
as inefficient debugging method as slowing of clocks can cause low utilization of
processor resource.

6
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
Conclusion:
This report has discussed the various aspects of Programmable Logical Controller (PLC).
Several important PLC programming techniques have been evaluated. Documentation of
engineering applications have been realized. The principles of coding online and offline have
been presented in the report discussing its usefulness and limitations. It can be fairly concluded
that the PLC programs do have its future with its simple form of coding. Programming data are
exchanged efficiently with a rather easy to understand diagram formats. PLC is cost effective
and full of customizable capabilities. The robust nature of PLC requires a lot less attention to its
maintenance.

7
PROGRAMMABLE LOGICAL CONTROLLER PROGRAMMING
Reference:
Netto, R. and Bagri, A., 2013. Programmable logic controllers. International Journal of
Computer Applications, 77(11).
Berger, H., 2014. Automating with STEP 7 in STL and SCL: SIMATIC S7-300/400
programmable controllers. John Wiley & Sons.
Huyck, B., De Brabanter, J., De Moor, B., Van Impe, J.F. and Logist, F., 2014. Online model
predictive control of industrial processes using low level control hardware: A pilot-scale
distillation column case study. Control Engineering Practice, 28, pp.34-48.
Joshi, R., Jadav, H.M., Mali, A. and Kulkarni, S.V., 2016, December. Integration of PLC based
offline impedance matching system for ICRH experiments. In Contemporary Computing and
Informatics (IC3I), 2016 2nd International Conference on (pp. 564-567). IEEE.
Zaremba, W., Sutskever, I. and Vinyals, O., 2014. Recurrent neural network regularization.
arXiv preprint arXiv:1409.2329.
Basile, F., Chiacchio, P. and Gerbasio, D., 2013. On the implementation of industrial automation
systems based on PLC. IEEE Transactions on Automation Science and Engineering, 10(4),
pp.990-1003.