Stop the pump with a condition?

[KRAZE4LV]

I wish to that in the VI the pump stops after the Pressure transmitter reaches a value of 5bar.

I tried to create a local variable. Please can some let me know the concept or how can I modify?

[TerraNova]

As can be seen from Your attachment, You've got four pressure gauges. Do You want to stop the pump when ANY of four transmitters reaches 5 bar or only the first one?

Regards.

[g_Ricky]

I have modified your VI, if one of the values read is over 5 bar the boolean become true. If you want to change the logical check and you want the boolean become true when all the values are over the limit, simply change the OR condition with the AND condition before the boolean variable!

[KRAZE4LV]

Thank you the modification.

I just changed the VI to check it.

1. I put the condition for 0.5 bar but it does not stop.

2. suppose I have two operations: pump start/stop and motor start/stop, So i want if any value in the array reaches 0.5 bar only pump stops but motor keep running and VI keep running.

How can I do that?

[RavensFan]

First, your local variable is called Value, which turns out to be your Stop button once I found the terminal and turned on the Stop button's label.  (I would have named the button Stop for clarity.  Terminals on the block diagram should always have their label shown so you can see what control or indicator they are for.)  So when you write to the stop button, you are never actually writing to the boolean control that turns off the pump.

Second, you are comparing your values to 0.5.  But the value is a random number (0-1) multiplied by 2.75 (So now 0-2.75) then 3.75 subtracted from it.  So now -3.75 to -1.  None of your values will ever be greather than 0.5.

[KRAZE4LV]

Thanks for the suggestion! I modified it.

Actually I used stop local variable coz if I use pump start/stop local variable the VI doesnt  run.

But I want that once the pressure value reaches 0.98 value, only the pump stops but motor and the Vi keeps running.

How can i do that? Please see the attached.

[RavensFan]

You are still writing to the local variable that is going to stop the VI.  You need to write to the local variable that relates to your pump start/stop button.

But if you only want it to stop, and not turn back on again.  Wrap a case structure around the local variable so that it is only written to in that situation.

PS, Rather than writing to the gauge and a numeric display (which are misnamed and mixed up), just turn on the digital display for the gauges.

[KRAZE4LV]

Thanks that realy helps!

1.If I want to run it on again how can I do that?

stop at 5 bar

start again if the pressure is lower..

2. Secondly, I want to put this condition only for one PT i.e if the pressure transmitter 1, then how should I do that?

[RavensFan]

Put in another case structure with the other condition that writes a True when the other condition is true.

And if you only want the comparison for one transmitter, then only do the comparison with that rather than the whole array of values.

[KRAZE4LV]

Please check!