I simply don't understand this.

Latzi · Jun 10, 2008

Hi Gents,

I am new with Siemens as probably a few of you already know.I did post a few questions before on this forum and with your help I managed to understand how Siemens Step7 works.Or so I thought untill now.I've made a program which I tried to simulate and everything works just fine except to the point where let's say I set a memory bit on Network 20 at address M1.0 called "System_Started_Running" but in the program that "System_Started_Running" is not available on network 17 before 20 where I set it.???????? Why?? This works without any further problem on any other PLC programming software I know about.How can you make a program then??I thought if you set a Boolean to true it will stay true throughout the program without further questions.This bit "System_Started_Running" is available after network20 but not before.Could somebody explain to me why??Please.

Jeebs · Jun 10, 2008

Unless there is another place where you reset this M1.0.
Or unless you configured MB1 as the Clock memory in the HW-config.
Or unless you transfer something to MB1, MW0, MW1, MD1, MD1.
.
.
.
It should remain True.

JesperMP · Jun 10, 2008

Latzi.

Post your ~~code~~ complete project.

Latzi · Jun 10, 2008

Unless all those it should.But it doesn't.Simulator for Siemens is "bugged up"???
The situation is extremely simple.I set a M0.1 at Network 20 reset at 21 under certain conditions but when I try to use the "open contact" on network 17 or 14 or 13 it shows up as opened????Very annoying.Is the simulator ok???

L D[AR2P#0.0] · Jun 10, 2008

The source code (in absolute format) would be better as I can't read the Step 7 Lite archive.
(From the block editor select customise/sources then check the tab to generate source code automatically - if this is available in Step 7 Lite of course)

Latzi · Jun 10, 2008

If I monitor the bit it comes up as true.??Even more stranger.I probably don't understand something.However what can be more straight forward than this.Set boolean M1.0 to true and try to use it throughout the program but it doesn't work unless you are after the place where you set the boolean to true.Has to be simulator.

L D[AR2P#0.0] · Jun 10, 2008

Remove all code that resets M1.0
Set M1.0
Report results

JesperMP · Jun 10, 2008

Yes, post as source, the I can run it in my PLCSIM too.

Latzi · Jun 10, 2008

I posted the source.The source is k7p file.Generated with STEP7 Lite.Please have a look.

Latzi · Jun 10, 2008

Code which resets bit removed.Exactly same behaviour.when I try to use

it comes up as open if I am above the network where I set it and closed under the network where the bit has been set.

L D[AR2P#0.0] · Jun 10, 2008

Here is an example of some source code. Copy/paste source code text.

Code:

FUNCTION FC 7 : REAL
TITLE =
VERSION : 0.1

VAR_INPUT
  a : REAL ; 
  x : REAL ; 
END_VAR
BEGIN
NETWORK
TITLE =
	  L	 #a; 
	  LN	; 
	  L	 #x; 
	  *R	; 
	  EXP   ; 
	  T	 #RET_VAL; 
END_FUNCTION

Jeebs · Jun 10, 2008

In the simulator > Execute > Scan Mode > Select Continuous Scan.

CharlesM · Jun 10, 2008

Keep in mind that the M0.0 is the same address as bit 0 of MW0. I had a lot of trouble with this when I was getting started.

Latzi · Jun 10, 2008

Jeebs,

I have it in continuous scan.As I said when I monitor it using monitor/modify feature it comes up as true.

L D[AR2P#0.0] · Jun 10, 2008

You need to post the source code in text form.

I simply don't understand this.

Latzi

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Jeebs

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JesperMP

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Latzi

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L D[AR2P#0.0]

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Latzi

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L D[AR2P#0.0]

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JesperMP

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Latzi

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Latzi

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L D[AR2P#0.0]

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Jeebs

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CharlesM

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Latzi

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L D[AR2P#0.0]

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