Mits AOJ2 questions from a novice

[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 off 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 figured out 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-something 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

[panic mode]

0) congrats on building SC09 look alike 1) there is GX Developer demo but for FX series PLCs and 1000 steps program size limit 2) not for that specific CPU but check posts in this forum and download section (there are general Mitsubishi tutorial which will do) 3) if the variable is in the register such as D100, you can do it by using MOV D100 K4Y20 (K4 is hardcoded value decimal 4 and indicates how many nibbles to pack togeter starting from Y20, nibble is 4-bit so 4x4=16bit) 4) why bother? i would rather focus on some MCU 5) not sure why you think it's RPN. instructions are prefixed not postfixed. anyway i don't have any info on this question. maybe someone else can help you

[MDH]

Probably "nibble" copying would be more to your liking if you're doing a major break down. V or Z are the more appropriate registers or variables. Y? because this isn't normally used... Mitsi has it's own unique set of un-understandable set of rules and addressing... And did I mention the help menu's,,, There isn't one.. Luck with the buffer memory stuff.. Thank god for the M and D info and we wouldn't know that if it weren't for the Meau sight... Used to be my bible until I passed 50... Let me know your sincere plight and I may be able to steer you in the right direction... Luck to 'ya

[MDH]

[Crossbow]

AOJ2 is extremely old, and completely obsolete. GX Developer is the Windows based programming software for the Mitsubishi PLCs. It does not support AOJ2, but it does support the more powerful sequel, the A0J2H. I would strongly recommend giving up the A0J2 and trying to get a cheap FX on Ebay. Then you can at least use that limited 1000 step version of GX Developer-FX. All manuals on A0J2 and A0J2H are available at www.meau.com.

[markaren1]

Hi Crossbow, et al, Thanks for all of your replies. Any ideas how much I might spend on an FX CPU with internal 230VAC psu and 16 relay+contact closure I/O ? I am having a difficult time navigating www.meau.com for manuals I seem to end up at http://www.nagoya.melco.co.jp/english/products/index.html which has plenty of stuff relating to the FX. I can find the FX CPU manual (JY992D48301) but there doesn't seem to be an option to download the document, do I need to set up an account ? Where are the AOJ2 manuals held ? Have they all been withdrawn from the site now ? Attached is my version of the SC09 interface. I used 26LS3x ICs that are more readily available that the other design I saw on the MrPLC site. Regards, Mark SC09.pdf

[Crossbow]

MEAU.com redirects people from outside the US. MEAU is the US company of Mitsubishi Electric, and so their site is designed to support the US and Canada. The Nagoya site is corporate in Japan. I don't know if you would need an account. Many people have been successful in using a redirector to get around the meau.com forwarding for foreign visitors, but I have no idea how to do that, being in the US it works fine for me.

[markaren1]

Yup, I can see my problems now. Thanks. ============ On a different topic I am trying to get T0 to count to 10 then restart (so it continuously counts with a T0 event every 10th count). Any pointers ? T0 K10 --|/|------(T0)---- T0 --| |------[RST T0]---- | ----[iNC D0] --- So D0 continuously increments every 10 T0s Thanks, Mark

[Crossbow]

The time period (K10) goes above the output coil, not the input contact. You do not need to reset the timer, as the logic will already do that. You know the PLCs all tend to have a one second clock pulse bit. I don't know the address on the old A0J, but it was in the M9000 range on the A Series. That bit would be off for 1/2 second and on for 1/2 second, so if you used INCP (pulsed) on that bit you would get the same result as your timer with a preset of 10 (1.0 seconds).