New to PLCs, several Mits AOJ2 questions

[markaren1]

Hi All,

I am new to PLC-anything (my background is embedded C) and have been given some Mits AOJ2s and I/O modules to experiment with. This is mainly education for me rather than any specific goal.

I have built an SC09 look alike, and have MELSEC MEDOC running (one saving grace is it's win32, so I didn't have to dust down a real DOS machine).

I am struggling my way through the AOJ2 programming manual and have some simple ladder logic running. More by luck than judgement I also have the Monitor Mode so I have some visibility into program behaviour.

Several questions:

1) Is there anything Windows based that is readily available that is less difficult than MEDOC in terms of User Interface ? I am of course interested in a further $0 investment I was told that FX Developer supports the AOJ2 but I can't readily find a download.

2) Are there any decent tutorials for the AOJ2 ? I have found quite a few reference books on the general subject of PLCs but the "AOJ2 Programming Manual" leaves a bit to be desired in terms of ease of understanding from a newcomers point of view.

3) I would like to output a 16 bit variable to Y20..Y2F. It looks like I should be shifting into M9012 then bit copying to Y20 etc. ? There must be an easier way (maybe using the Y or Z registers ?) Any other easy methods I should investigate ?

4) Has anyone done anything extremely daft like make their own peripherals ? It seems like a reasonably simple bus with an HC85 magnitude comparator for device selection...

5) It looks like the machine is stack based (hence the RPN style of programming). Are there any other details about the core of the processor / interpreter model ? I am mildly interested in cooking up some other form of programming interface - transfer protocol and machine instruction bit patterns would be very helpful.

All comments gratefully received.

Thanks,

Mark

 

[parky]

Generally you don't get free programming software.

To copy a 16 bit word to outputs then just use the mov instruction.

[mov D10 K4Y20] The K means constant to move a word to bits K1 = 4 Bits K2 = 8 bits K4 = 16 bits etc.

The above will move the bit pattern in D 20 to Y20-37
Mitsubishi will hold the interpreter a closely guarded secret & if you intend using a plc in a machine it's best left alone, Why change something that works & has been tested in thousands of applications.
PLc's are designed in most cases so they shut down outputs in the event of corrupt, invalid code or faults for safety reasons.
It takes plc manufactures years to develop the systems & test them.