commanding PLC without using PLC input ports. how?

Well actually I should be writing a progress report to my lecturer about my final project, but I can’t wait to write something on this peaceful blog. LOL. Since Azam told me that I haven’t written for more than a month. I’m not like him, I’m not kinda man who has alotta ideas to write on, except for writing shameful stories. LOL (which I’m quite good at).

Ok, so the story today is about system integration. I currently still try to accomplish this (still far out of my reach) project on Visual Servoing on PLC Based Cartesian Robot. This is really basic in Visual Servoing, so I think the problem rise then is mostly about the system integration, not control systems. So this Cartesian robot actually is used to simulate a Pick-and-Place process like those in industries. And the Ladder program is already available in that Mitsubishi FX2N PLC with that algorithm of pick-and-place task, which mean that I don’t need to write ladder on that PLC anymore. Even though actually I planned to make a simple fuzzy controller algorithm on the PLC, but then I had to cancel it for the IO of that PLC is digital IO. Yes, I can’t control the speed of the end-effector of the robot. It’s just simple on-off control or Proportional control scheme.

Well, I’m a bit disappointed with that IO. But, it doesn’t mean that my task is much simpler today, because I need to make an interface between my image-processing PC and the PLC. I had been thinking that the main problem was gonna be about the control system, control algorithm, image processing and other programming tasks. In fact it’s hardware things coming out!!!

Yes, I’m still bad at hardware integration. So, the plan is to make a simple demux for transferring control signal (which in this case is not different from error signal) to the PLC. Perhaps I’m gonna need a typical ATmega microcontroller for this. Unfortunately, so far this demux remains a dream.

So I come up with another idea, commanding the PLC without using PLC Input. This robot comes with a touch screen GOT(Graphic Operation Terminal) panel HMI (also from Mitsubishi) which doesn’t directly command PLC trough it’s input. I try to find out how to do this, accessing PLC device memories by connecting PC and the GOT 1000 with a USB, or using an RS 232 which usually used to download program to PLC.

Any idea about this integration?
Is it possible to command the PLC from PC trough this GOT 1000 HMI panel?