Indirect addressing with GX Developer

DairyBoy · Jun 13, 2007

Good day All.

Indirect addressing; AB...OK, Indirect addressing; Omron...OK, Indirect addressing; Mitsubishi Q series...HELP! Yes, I have looked it up in the book, but it just won't sink in. By the looks of it I won't be able to indirectly load timer values without a proxy register, but my addled brain is struggling with even the D-register to D-register stuff. Would some kind person please post a one-liner to show me how it's done? Many thanks.

Mchl · Jun 13, 2007

Not sure if this is what you would like to do:

Code:

  |-|LD X0|-----------(OUT T0 D0N0)-|

Now. When N0 is equal to 0, then the timer takes its timelimit from D0 register.
When N0 is equal 1, it takes timelimit from D1 register, and so on.

DairyBoy · Jun 13, 2007

Mchl, Thanks, but the editor throws out the structure that you suggested (only one address allowed in the t function), but I'm still looking for a way to move say, the data in D0 into another D register @(value in)D1. If D1=3, then move contents of D0 into D3, etc.

Pierre · Jun 13, 2007

This?

DairyBoy · Jun 13, 2007

Pierre, It looks good. I've tried it on the simulator with D registers and it works ok. Q: There is a limit of Z0-Z9, so is it safe to use (for example)Z0 many times in the program as long as the loading of Z0 is next to (immediately before) the rung that uses the Z0 to do the pointing? So it just gets reloaded "locally" wherever it's needed in the program?

504bloke · Jun 13, 2007

Yes

From the Mitsubishi FX2N Programming manual

Mchl · Jun 13, 2007

DairyBoy said:
Mchl, Thanks, but the editor throws out the structure that you suggested (only one address allowed in the t function)

There's a good reason for that. I mixed up Z and N registers (somehow this happens often to me...). Of course in the example a Z register should be used. N go for Master Control Nesting (see MC and MCR instructions)

DairyBoy said:
, but I'm still looking for a way to move say, the data in D0 into another D register @(value in)D1. If D1=3, then move contents of D0 into D3, etc.

For this you also use N...arrr... Z registers, but it has been shown to you already.

Also: Q02 and up give you a total of 16 Z registers. Not much, but apparently sufficient for most uses.

DairyBoy · Jun 14, 2007

Thanks everyone. I've run some experiments in the simulator and all come out as predicted with this new information. I like the idea of an implicit offset in the function; very useful for indexing chunks of contiguous data from different areas in the database. But then, that's probably why they did it...

Indirect addressing with GX Developer

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