A brand new week, brand new adventure awaits! Can't wait to explore them all!

Today's traffic was a breeze. Most of the traffic lights are green. Slowed down but still arrived at Puchong before 8am. Speaking of traffic lights, today is all about them, literally! As soon as the office was opened, i was given my first assignment by Mr. James. Its about PLC! I was tasked to design a PLC program to control four traffic lights that runs sequentially. PLC is quite an alien to me. Have only been exposed to it briefly in Control Systems subject. Learned about it on the web but quite a challenge for me to comprehend it.

Like I said before, it uses the ladder diagram to program it. Its TOTALLY different from the usual C++, assembly and Boolean Algebra programming. Yes one would need to construct the flowchart prior to program using any language listed above but converting a flowchart to a ladder diagram is tougher than I thought! Before I go further, lets refresh on what a PLC is.

PLC is a replacement of a myriad of relays that controls a machine. Think of it like a million transistor cramped into a single integrated circuit. The transistors represent relays and the IC is the PLC. Except that a single PLC device has very limited input and output relays. A PLC can come from many different brand such as Omron, Siemens, Toshiba and Schneider. Each brand has its own software for programming but the technique does not differ much from each other. Mostly the only difference is the interface. Today I'm using PLC from Schneider and the name of the program bundled with it is ZelioSoft 2.

The first moments was extremely difficult for me. I have no idea what to do, what this symbol stands for, how to simulate or in short, I know NOTHING!! but that never stopped me. I remember there's one quote posted somewhere in UNITEN that goes something like this, "The purpose of education is for the student to educate themselves". That quote kept me going. I'm not just going to stare at the monitor hoping that I will magically understand something! Lets try something out!

After a few minutes fiddling with the icons, I started to go, "Oooooooooooo macam tu rupanya...". With additional help from Mr. James, I begin to understand the logic of each icons and what they do. Vital key statements from Mr. James like "To activate this you must have the coil", "When this coil is on it will activate this switch.." assisted in my understanding tremendously. The help files are a great help too. Here's what the program looks like and what I have done so far:

With trial and error through the simulator, I slowly find a suitable program sequence to get a desired output sequence. So far I've almost successfully completed the first two traffic lights. Still have a few issues to solve before moving on to the third and the fourth traffic light. To me this is about the toughness of the MicroP subject. Thankfully I managed to learn a lot about it in just one day.

Today I learned two key attributes an engineer must acquire that is to be able to solve a problem with very limited information and resources, and to be able to learn new things quickly using whatever means available.