SIEMENS Step 7 300

Join Date
Feb 2014
Location
Houston
Posts
19
Hi All,

I am new to Siemens, and trying to implement a logic state below.

Have 5 valves to open for certain time in Automatic and Manual. I got Automatic by adding 1 after each valve has open for certain time.

Now with Manual selection of valves i have to implement the same sequence.

For Ex. If the operator has selected 1, 3 ,5 valves out of 5 valves then the program should open 1, 3, 5 in sequence one at a time for 10 sec. so the program should adjust to operator selection. as he might choose 2,3,4,5 for the next manual sequence.

Thanks
RV
 
Let me see if I understand.

Auto/man switch. If in auto the valves will open like this:
0-10 secs: 1 open
10.1-20 secs: 1, 2 open
20.1-30 secs: 1, 2, 3 open
Etc

If auto/man switch is in man mode then plc looks at at the state of the switches for the individual valves. For example 1, 3 and 5 are on.
Always open from smallest to largest.

0-10 secs: 1 open
10.1-20 secs: 1, 3 open
20.1-30 secs: 1, 3, 5 open


The way I would do it, would be using a sequential flow chart/grafcet type program written in SCL.

Basically have OB30 I think it is increase a variable by 1 every 100ms. When you press start, count the number of valves to be opened and which ones need to be opened.

Then use a load of if elsif and > to turn to valves on and off.
 
Hello Diameter

Thank you for replying for my post.

But here is the thing i dint have the Graph Package on my Step 7 all i have is STL/LAD/FB.

Also i think i didn't convey right.

Example :
I have to make two Modes Operator Selection Mode and Auto mode
1. Auto Mode
I have 8 ON/OFF valves with feedback and i have to Open Number one (1) valve and only one valve at a time for lets say 2 min and while doing that i have to make sure all the other valves are closed then once the Number One valve closed i have to open the number 2 valve and so on till Number 8 valve and once i complete number 8 valve i have to restart from 1 with a time delay of 1 hr as long as he is in Auto Mode.

- Which i have executed by Adding one to each step and comparing it. - Worked Ok i am not sure if this is the efficient way to do or not.

2. Operator Selection Mode
Here i have to give the operator ability to select the valves he want to open and close like above.

so lets say the operator from graphics selects 1, 3, 4, 7 and 8 valves to open and close that means the cycle should be
Open Number one (1) and only one valve at a time for lets say 2 min and while doing that i have to make sure all the other valves are closed then once the Number One valve closed i have to open the number 3 valve and then once the time is done close and open 4 and once 4 is done close and open 7 and then once 7 is done close and open 8 and restart the same sequence with a time delay of 1 hr.

Thanks
Vamshi
 
Add some logic to each step that causes it to skip to the next step if in manual mode and the operator has not selected that valve for operation.

(Copy your blocks to a library, archive the library and then post on here if you want your code looked at)
 
If your company has a license for tia portal, it is easier using that as long as it's at least version 13 or so, lower versions are unstable.

If you only have access to the older "classic" then you can use SCL code like this:
https://m.youtube.com/watch?v=tc3_IlAjHiw
https://cache.industry.siemens.com/dl/files/131/18735131/att_80275/v1/GS_SCL_e.pdf?download=true

It is doable writing this code in FBD or ladder, but I would find it easier and shorter in SCl once you get used to it, especially in TIA
 

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