M221 and SoMachine Basic - Indirect Addressing?

Hi All,

First project using the Schneider M221. Simple valve control where I have to open a valve to a fixed position depending on time of day. There are 17 different "time slots".

What I was hoping to do was simply build an array of valve positions, and step through it using a timer. After the timer expires, move next timer value into present, move valve position from array to valve positioner. Re-sync to RTC once a day (accuracy is not super important).

If I had a Micrologix I'd use indirect addressing. I can't seem to find anything similar for the M221? The drum instruction is laughable - only 8 steps!

I can brute force it but it's just nasty. This is only going to be running this system until summer when we can get a proper system installed.

Thanks!

Look from M221 help indexed addressing.

%MW200:=%MW100[%MW0] on operate block is syntax.

%MW0 = 0..17

-> %MW200 have values from words %MW100.. %MW117

You can use words only

p.s 17 different times Would it be easier use 24 (hours) directly to index if accuracy isn't important?

Awesome, thanks Lare.

Yes it's silly I know. I think the accuracy is not that important but our process engineer is one of those "in theory" kind of people. 80% of the time the valve changes position on the hour, the other few hours the transitions occur at varying times within the hour. I have 3 graphs and a very big excel table provided as proof of his reasoning.

So adjustable look up table is easiest then he can spend days tuning this thing in the snow, while i sit back at the lodge

hmm, how you program it indirectly. Brutal compare method would take some 18-20 rungs with PLC clock.

With timer and count up, and ajusting it every day it isn't much shorten to program

I'm still using the PLC clock, not a timer. Using indirect reference only took 6 rungs for the counter, compare and move logic for the valve position. All good, thanks for your help

Not bad