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Messages - Gizmobreaker

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Technical support / Re:random behavior desired
« on: February 19, 2007, 09:58:14 AM »
Since the PLC will run unattended, all day, I am thinking that perhaps the best way might be to create several (depending on how many programming steps it takes) lists of steps and use a sequence counter as an input.  That way if the sequence value is 1 then it will run the first list, if the value is 2 then it will run the second list, and so on.  Lots of keyboard time to get it done, but I cannot think of another way to vary the procedure from run to run.

Along those lines, the program length limit is 400 steps, I believe.  Does that include ladder rungs used only for comments?  Is it a count of rungs or lines?  In InstallationT40.pdf I see that a step is roughly equal to a NO or NC contact.  Does that mean that if there are 4 NO contacts on a ladder line, it uses 4 steps?

Thanks again,
Marty

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Technical support / random behavior desired
« on: February 19, 2007, 06:48:09 AM »
I am using a T40H-Relay controller.  I chose it because the relays are on the card and I have very limited space.  The first 12 relays control lights and 15 + 16 control an MP-3 player.  The lights turn on in 1 second steps according to a plan from the artist.

The timing chart looks like this (summarized):
60 seconds of 1 second light displays
60 seconds of lights 11+12 on steady
3 minutes of music
60 seconds of lights 11+12 on steady
go back to the start

Since the 60 steps of lights 1-10 are pre-programmed, the artist would like to re-enter the list at a random point each cycle to avoid the lights looking like they are repeating.  So if I start on step 1 the first time, I would like to start on step 7 the second time, or something like that, then loop through the steps.

If I was using a more complex language, I could generate a random number and use math to control the steps.  In the past I have used IDEC's PLCs to do that, but they are too big for this project.

Thanks for any help,
Marty

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