SB 13 does not work as expected (V280)

[kilca]

Hello,

 

first please accept my apology for my bad english.

 

I`m using SB 13, which should do a pulse everytime SB 3 rises (every second). I`m increasing value by INC function block by positive transition contact of SB 13. Works well for like a minute and then it starts increasing around 50 values per second. It lasts for around 5 seconds and then it goes back to normal. When I`m watching online test and this situation happen, the ---[P]--- of SB 13 starts flashing a lot.

 

Joining my VisiLogic project. (there are unconnected nets and timers, please, don`t give it attention)

 

Thanks in advance for quick reply.

 

Best regards,

Martin Půta

V280-2016_15_5 (1).vlp

[lawry]

For SB13, you donot have to use Transistional contacts. Replace with NO Contact

[cantcliff]

I did not load your ladder as I don't have access to software where I'm at to run it.

 

 

It may be the way your logic is running.

 

If you're not catching a rising or falling edge, as long as your increment function is active it will increment each scan when the pulse is active.

[Gabriel Franco]

Do not use positive transition of SB13, instead, use N.O. contact.

[Flex727]

SB 13 should only be on for one PLC cycle. However, I notice that you sometimes use a positive transition contact and sometimes use a direct contact for SB 13. I don't think it matters which one you use, but you are limited in the number of positive or negative transitions you can use in your project. I also notice that you sometimes use the increment function and sometimes use the add function to increment. Why the inconsistencies? I also notice that rung 2 of subroutine Trendy-24h is not connected to the left rail.

 

None of this is the cause of your problem, but I don't have a V280 handy to load your software and troubleshoot. You have 8 instances of SB 13 incrementing integer operands - are all 8 acting abnormally, or just one?

[kilca]

Thanks to all for the input!

First, the positive transition contact was a mistake. I was using classic direct contact since beginning. But because it doesn't work as expected, I've tried everything that came to my mind.

to:Flex727
"Sometimes this, sometimes that". Yes it's true, but it's only because I'm trying variations that came to my mind when something is not working for me. So that's why I'm having there inconsistencies. Unfortunatly it doesn't work either. And about that rung 2 of subroutine Trendy-24h I know. Another part of me trying to solve things. When I want to try something else, i rather disconnect it then delete the whole thing so I can reconnect it later.

All 8 instances are doing the same thing. It's all about the SB 13. It just starts flashing for few seconds and the pulses are like 50 per second, not 1 pulse per second as it should do.

 

Best regards,

Martin P.

[Flex727]

When I wan't to try something else, i rather disconnect it then delete the whole thing so I can reconnect it later.

 

Just right-click on the left side of the ladder rung and select "Disable".

 

When you're troubleshooting you need to isolate the problem as best as you can. Do NOT assume that there is something wrong with SB13. It will reliably pulse once per second. It cannot fail to do exactly that. Add a new ladder rung to the Main Routine to increment an unused MI with SB13 and you will prove that to yourself (I see MI2047 is labeled "test" - maybe you already did that?).

 

Make sure you don't have any vectors that are overwriting your values also.

[kilca]

Just right-click on the left side of the ladder rung and select "Disable".

 

Thanks, I did not know. This is my first use of PLCs and ladder logic completly. I'm sure that I'm doing more mistakes. I've already tried increment unused MI on SB 13. Vectors should not be in range of MIs/DWs i'm using to increment. But I will check both again tomorrow morning (it's midnight here in Czech Republic). 

I will leave you message here after further investigation in the morning.

Thanks again for trying to solve this with me.

[Flex727]

Making mistakes is the fastest way to learn! 

[kilca]

Sorry for not responding for 2 days, I've been busy with other parts of my project I had to solve preferably.

 

Making mistakes is the fastest way to learn! 

 

Yes indeed, then I can state that I'm learning the fastest way possible

I've checked what you said about the SB 13, still nothing. I need your advice in another thing what have the highest priority for me at this moment.
I'm displaying trend where is shown produced power from solar panels in last 24 hours. I'm having problem with "time axis". As I refered before, I have time stored in one DW. I need to get out of it what hour is at this exact moment. I want to have the X axis chopped on hours. For example, when it's 4pm, point before will be showing 3pm, then 2pm and so on. Calculations of the axis won't be problem. But I can't figure out how can I get exact hour number from the DW. Any suggestions?

Much thanks in advance!

Martin P. 

[kilca]

Oh my god. Forget the problem with time. I find out the UTC to RTC will do everything I desire! OK, we are back to SB 13 problem

[kilca]

Since my last post was not approved apparently, I`m trying my luck again.

 

I`ve cleaned program, deleted nets which was not used anymore (test nets etc.) and after few days it looks like it`s working good. I can`t explain you why, but it`s working and that`s important for me I`m now fighting with the very last thing I have to do with my project and I started new topic on forum since I think that it could help others too.

 

http://forum.unitronics.com/topic/4124-basics-of-modbus-communication-via-rs485/

 

Feel free to join the discussion.

 

Thanks everyone for the inputs!

 

Martin P.