Indirect Addressing Plc
Plc 5 Io Addressing
Jan 02, 2002 The PLC-5 and SLC-500 use a rack/slot/register/bit method for addressing the I/O modules. For example input point 15 in slot 2 of rack 1 would be addressed - I:1:2/15. The same goes for outputs. Now the legacy problems prop up. In the old days most things were octal so AB allows for different methods for addressing modules in the rack. Q1: If there are no 'un-assigned' slots according to the addressing type, and no size of rack, then yes. The 'span' for chassis 1 is 1/0-1/5, meaning 6 words, which will cover the entire 12-slot chassis if 2-slot addressing is used. So my guess is 'yes'. Block Transfers use the 1st word assigned to the slot. Dec 20, 2013 If I use Allen-Bradley PLSs, the module numbers start with 0. So all the addressing is screwed up. Is it possible to change module numbers? Is there a work around? If I go to module properties, after insertion, and chalge slot number, the module dissapers from PLC manager, but still present in the Components tree!!!
Plc Addressing Guide
This is how I keep it straight.
If you want your card arrangement totally unrestricted, it follows this pattern:
2-slot addressing = 8 point cards
1-slot addressing = 16 point cards
1/2-slot addressing = 32 point cards
I think of this as the 'default' configuration.
If you can tolerate alternating input cards and output cards in pairs, it follows this pattern:
2-slot addressing = 16 point cards
1-slot addressing = 32 point cards
1/2-slot addressing = not useful
I think of this as the 'upgrade' configuration. Many older PLC-2 and PLC-5 PLCs were originally installed with 8 point cards and 2-slot addressing. Over the years they were upgraded by replacing 8-point cards with 16-point cards. For example, if you had 2 8-point output cards in the same module group, you could replace them both with one 16-point output card and gain a spot for a new 16-point input card.
I don't think I would ever build a new system with alternating input and output cards. The ratio is usually more like 4 inputs for every output in my experience so I don't find that arrangement very useful. But when you need to squeeze a few more I/O into an existing system, definitely.