Remedial latter logic.

[itsmoked]

I have twenty identical logic blocks. Each one needs to block all the others from initiating until the active one completes.

I am looking at pages of relay logic to make each 'block'.

Any better suggestions?

Modicon.
Networks limited to 11 by 7 element arrays.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Hi Keith;
Are we up against the "If it ain't broke, FIX IT" and if it works, CHANGE IT" school of design? LOL

Can you confirm a couple of my assumptions please?
Assumption #1. This is programed in ladder logic.
Assumption #2. For a small segment, the scanning will be in the following order: Scan order denoted by S1, S2, S3, etc.

First option
Segment 1
network 1
Column 1 Column 2 Column 3
Row 1 S1 S4 S7
Row 2 S2 S5 S8
Row 3 S3 S6 S9
Solve Solve Solve
Logic Logic Logic

Second Option
Segment 1
network 1
Column 1 Column 2 Column 3
Row 1 S1 S4 S7
Row 2 S2 S5 S8
Row 3 S3 S6 S9
Solve
Logic

Third Option
Segment 1
network 1
Column 1 Column 2 Column 3
Row 1 S1 S4 S7
Row 2 S2 S5 S8
Row 3 S3 S6 S9

network 2
Column 1 Column 2 Column 3
Row 1 S10 S13 S16
Row 2 S11 S14 S17
Row 3 S12 S15 S18
Solve
Logic

Segment 2
End of third option.

The place in the diagram (Relative to nodes, columns, rows, networks, and segments) where the PLC stops scanning to solve logic and set outputs is very important.
And a question, can you define a relay or output in one network and call up contacts from it in other networks and/or segments. I assume the answer is yes but it's best to confirm.
Respectfully

 

[itsmoked]

Waross; I'm in the school of poke-it-with-a-stick-see-what-happens.

According to the Modicon book of PLCs.. It is the first option EXCEPT the logic is 'solved' after each node not at the bottom of a column.

http://i5.tinypic.com/11t1kyx.jpg

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Hi Keith
You may have better luck keeping your "Networks" as small as possible.

I would not use more than one coil or output per network.
If I understand the scanning correctly, that would give the closest operation to line by line scanning.
I'm on my way out the door. I'll have more time tommorow.

I have a tendency to try for full utilization. Get as many commands on a line and as many lines in a network as possible.

With this PLC I think that I would try to reverse my tendencies and use as many networks as possible.

My previous comments re: design were directed at Modicom, not you. The few modicom models I have worked with each had a completely different scanning protocol. I Hope I didn't inadvertantly offend you.

And I have more than once resorted to the "Poke it with a stick" school of troubleshooting, with surprisingly good results.
Respectfully

 

[itsmoked]

No! No offense at all... Yer too sensitive. How could you ever survive in a thread with skogs... hahahahaha

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Keith
If you know what I mean by "You don't have to study "Civil Engineering" to be a "Civil Engineer", then you read the same thread as I. LOL
I hope GE accepts this as humor and not a dig.
Respectfully