Old BBC language question

[SixDasher]

We have a machine with an old BBC plc (no type listed, beige/off-white modular plc). On a printout of the original program is lists the foloowing:

!N T 00.01
= T 00.01
= M 00.07

!N M 00.07
= MA

!N M 00.08
= M 00.08

! ME

!M 00.08
= A 05.05

Can anyone tell me what the MA and ME mean in this story? I am retrofitting with an S7-300 and don't get what they are trying to do in this routine because of the MA/ME relation.

My eternal gratitude to he who can show me the light

 

[kb9ttx]

I should caution that I have never used an ABB or BBC plc. Nonetheless, I did some internet searches trying to find information that would help me understand your example code. I am assuming that you probably know that this is IL type code. I also assume that you probably understand the content of the code better than me.

I assumed that ABB would not easily give up its intellectual property even if it was clunky and out of date. I figured if I look at their older manuals I would find residue of the old BBC syntax carried forward to their ABB PLC products. So I started by reading old ABB manuals looking for clues to the syntax. After looking at PDF after PDF after PDF, I started to see similarities to your code sample.

First, I learned that ! means "start of sentance", basically it means the beginning of a line of instruction.
Second, I learned that M 00.07 is an internal bit; however, I did see them referred to as a 'binary flag'.
Third, I learned that T 00.01 is a timer.
Fourth, !N means 'start of sentance with negation'.
Fifth, MA means start of label and ME means end of label.

Hopefully, that helps a little. You can try to decipher more yourself by looking at the programming manuals at:
http://www05.abb.com/global/scot/sc...cfbc1256e390040cc1c/$file/2cdc120133m0201.pdf

and at

http://www.abbplc.com/abbadvantac31manuals.php

Good luck

 

[SixDasher]

Hi KB,

Thanks for your post! All the code was clear except for the ME/MA part, thank you for your effort and showing the meaning of these commands!!!!