Positive Transition Bit Remains ON

[vasovas]

Hi, Guys,

 

PLC SAMBA SM35 J R20

I have a RESET button on positive transition, that randomly remains ON, like shown on the screenshot attached. 

It is a problem, because it reset counters and I get wrong data collected.

Any suggestions?

 

Regards,

 

[Ausman]

Right click whilst hovering on MB 0 and choose Find.  This will bring up any other references to  MB 0 in your project.   This is the first thing to look for....perhaps you have missed something else that is inadvertently using the same MB.  Also do the same thing for your other operands in case they possibly have the same problem.

(All programmers say their programs work perfectly the first time.....This is a fib!)  

The other thing it might be is an actual switch issue.  If it's not an onboard button, physically disconnect your switch AT THE PLC to check if this is the culprit.  If this  helps and the remote switch seems ok, it might be induced voltages in the input line.   If it does use onboard touch stuff, change it slightly.  Also check you haven't got a bit of dust under a screen protector etc.

cheers, Aus

[vasovas]

Hello, Ausman,

Thank you for your reply.

The button requests password to be entered (hence "legal entry" element link), but how it might be related to the issue?

[Ausman]

I don't know Sambas well so don't know for sure, I'm a 130 man.  But a trial would be to change your code a little, so that legal entry only remains ON for one scan and you don't use the positive transition at all.  In a 130 it stays on until enter is again pushed, which is sometimes confusing.  Perhaps something like this is upsetting things...but I can't see how.

Also, before doing anything else, have you done an Init and Reset?  Or a load blank program, Init and Reset, reload you program and Init and Reset?

cheers, Aus

[vasovas]

I use M6 bit in SCADA like trigger for some calculation , so I would prefer not to do any changes in the code for the time being.

And besides, sine the same code is running on 9 machines, I have noticed that the issue presents only some of them only.

A first chance, however, I will do Init and Reset, to see the outcome. Thank you, Ausman!

[Flex727]

7 hours ago, vasovas said:

Any suggestions?

 

Regards,

Try adding a Reset of MB 0 to the ladder rung above - just place it immediately below MB 6.

[Gabriel Franco]

Check rise/fall summary after compiling your project. 

It would be rare you have more than 1023 in Samba, but, just in case.

 

[Cara Bereck Levy]

On 11/9/2021 at 12:11 PM, Ausman said:

(All programmers say their programs work perfectly the first time.....This is a fib!)  

 

Right up there with 'it works'...you must be doing something wrong..'

[Flex727]

On 11/9/2021 at 1:01 AM, vasovas said:

like shown on the screenshot attached. 

It is a problem, because it reset counters and I get wrong data collected.

Any suggestions?

 

Regards,

Taking a second look at this makes me wonder if you're not misinterpreting this. MB 0 shows to be on, but it does NOT show power flow to ML 0 and the others. Actually, it shows that ML 0 and ML 1 are NOT at zero and are NOT Reset.