Popular Coding Conventions

I have worked on PLC's for several years purely on a maintenance basis (What's wrong, There it is, Now it's fixed).

I have recently started working for a company writing software from scratch, and additions to existing PLC code.

Are there any generic popular coding conventions, such as:

1. Critical Interlocks.
2. Auto Interlocks.
3. Manual Interlocks.
4. Plant Healthy.
5. Plant Enabled.
6. Drive Logic.

At the moment, until I obtain a degree of confidence over a period of time, I am having to learn cold turkey fashion.

I whole heartedly understand that it varies from application to application. But any tips for a relative newbie to project programming from scratch would be much appreciated.

Cheers in advance.

KB

I usually start with developing alarm logic. It's what I like to view as soon as I bring up the logic.

I take it you have started building up I/O tables and constructing program flow, so you have positve direction of where you are heading with your program design, what you want it to do, etc...

Yeah, I've got the baisc theme. The process flow I can obtain from the FS.

I have built my IO Schedule for this one particular project. I've started with the E-stop logic, which is mapped to coils which are read into the SCADA application. These are then series up to create an Critical Interlock. The same thing will apply for the Auto/Manual Interlocks. In turn these will be used to drive a System Ready Coil.

This System Ready Coil will be used on each drive along with a 'Drive ON' with the logic specific to the drive after that.

Does this seem like a suitable approach? This is what my last firm used to do (give or take a few things).

Any comments would be useful.

Cheers

KB

code

A good programmer is someone who has learned 1)it is the economy of code not its complexity that defines good programing. 2)there is more than one right way to do somthing. 3) if your program is getting long and complex, it is better, somtimes, to start over. If you know the process or machine and how it is suppose to work, it is easier to write code to get it running safely.

Have a good week, dont forget to have fun.....Bruce