Latches Output

[kikep]

Hi teachers I new on this, i just start to programing on visilogic but i have a small project, with 5 sensors and 5 valves connected to output on plc v350, but the problem i have is on HMI u put a Button to active for example ouput 0 only if input 1 is active, thats works active the valve but i dont find the way of valve stay open until i pushed button againg to unactive the valve, i think could be something like latches o exist another way to control that.

 

thanks..

[Alexander]

Moved to Visilogic forum

 

Yes, this is absolutely possible. What you will need to do is use the set coil function. This will allow a bit (output or MB) to stay active indefinitely until a reset coil function is called to set the bit back to 0.

[Flex727]

You can also use a "Binary Text / Switch" and check the box for "Toggle". You can then use the ladder to Reset the bit or Output, if needed.

 

I like this method because the operator can "see" that the Output is on and can also turn it back off manually if necessary.

[Joe Tauser]

It's always helpful to post your code when you have programming questions.  One of us can edit it and post it back, showing what we did.

 

Joe T.

[navigatoru]

Hi guys, 

 

I understood how can I latch an output. It is very easy with the Toggle option in VIsilogic. Now, my issue is on how to "pulse" an output. Using the toggle option I can not reset the latch ...

Basically I need a button on the HMI display which will "pulse" an output when is pressed for 100ms. I know that it is possible by using a set coil after that a timer(100ms) and after that a reset coil for the output, but I could not find how to proper program the ladder. 

Any help would be greatly appreciated.  

 

Thanks

[Alexander]

As you described you can use a coil triggered by pressing the button, and this can power a timer with a preset value of 100ms. You can then reference this timer as a positive transition contact within the logic connected to a coil for an output.

 

Using this logic the output will only be turned on for one scan if you want to pulse an output. If you wish for the output to remain on for more than one scan or a period of time you can set a coil for the output and use a second timer to turn off the output after a desired time.

[navigatoru]

As you described you can use a coil triggered by pressing the button, and this can power a timer with a preset value of 100ms. You can then reference this timer as a positive transition contact within the logic connected to a coil for an output.

 

Using this logic the output will only be turned on for one scan if you want to pulse an output. If you wish for the output to remain on for more than one scan or a period of time you can set a coil for the output and use a second timer to turn off the output after a desired time.

Thanks for your answer. Is exactly what I was thinking, but my issue is that I am not able to put this expression in a ladder. I tried to put a button on HMI, I assigned a (mouse click) MB30, I continued in the net with a timer (Store>Load TimerCounter Preset), and finished with a coil (for Output), but nothing.

There is a tool somewhere to debug the code line by line? Basically to see the output for the ladder ... 

As I said in my previous post, with the Toggle option, I can assert the Output, but I have to press again the button to deassert the output, which is not exactly what I need. 

Any help is much appreciated.

Cheers, 

Marius

[Alexander]

Once you download your program you can go into Online Mode which will show the power flow of the logic rung by rung. You can also see any numeric or timer values in real time.

 

After testing in online mode, if you still have issues, please post the code to the forum so that we can make any recommendations.

[Joe Tauser]

Read the Help on the TE timer type.  It will do what you want.

 

Joe T.