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STEP 7 / STEP 7 Lite

Is it reliable to create a sequnence in STEP7 with LAD (FBD)

Thread Starter: alexfizeau   Started: 1/22/2007 8:33 AM   Replies: 3

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  1/22/2007, 8:33 AM
alexfizeau
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Many thanks for your replays. I have another technical question. If I do not have SFC or CFC to create a sequnence in Stept 7, it is reliable to create it with LAD (FBD) using timers to set the transitions and steps ? Or there is any other way ? My sequence should by: execute this and that, when conditions are fullfilled stay in this state for a time (start a timer and count), after timer has elapsed, execute that and that... and so on... Many thanks.



=== Edited by CS Moderator @ 1/22/2007 10:42 AM [GMT ] ===
Question was posted in another thread.

new subject after splitting

[Project Lead Engineer]
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  1/22/2007, 9:13 AM
Aret
Joined 10/31/2005
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You can use LAD/FBD for this purpose. As for other way i would recommend using jump list work making steps.
For example

//Using timer - step 2 is wait for 1 minute after step1
L #step_number // NOT temp variable
L 2
==I
SD T1

L #step_number
JL err
JU stp1
JU stp2
JU stp3
....
stp1:
A condition
JCN end
//Condition fullfilled - make some actions
L #step_number
+ 1
T #step_number
JU end

stp2:
A T1
JCN end
L #step_number
+ 1
T #step_number
JU end
....
end: NOP 0

Note, that it's better to use all timers handling outside jump list. This would allow timers to get 0 on when current step not equal step needed. This would allow timers to restart correctly.



=== Edited by Aret @ 1/22/2007 9:14 AM [GMT ] ===
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  2/15/2007, 9:30 PM
Marcio
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Hi,

If your CPU has the SFB 32 ("DRUM"), you can use it to implement a sequencer with 16 steps. This SFB has many operations mode.

I never used himlaugh, because I always use the S7-Graph for sequential process.

Márcio Santos
www.marcioroberto.wordpress.com
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  2/16/2007, 6:55 AM
usjwo
Joined 1/13/2006
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Hi,
 
Below short and simple example
 
MW0 - Sequence steps word
M0.0 - 1st step,
M0.1 - 2nd step,
etc...
MW2 - Transaction word
M2.0 - from 1st step to 2nd step,
M2.1 - from 2nd step to 3th step,
etc...
 
L MW0
L MW2
AW
==I
JCN NTR
SLW 1
T  MW0
NTR: Nop 0
 
You must add the some conditions for first and last step, and should works.



=== Edited by usjwo @ 2/16/2007 7:02 AM [GMT ] ===
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