alarm system for gas pressure

[mae2007]

Dear Friends
I want to design a circuit to detect a gas (as compressed air) pressure and makes alarm in the event of pressure drop.
- the pressure may be between 2,5 to 5 bar
- I want to use LM324N as comprator
thanks for help

 

[Leftyretro]

Dear Friends
I want to design a circuit to detect a gas (as compressed air) pressure and makes alarm in the event of pressure drop.
- the pressure may be between 2,5 to 5 bar
- I want to use LM324N as comprator
thanks for help

Well first you need to come up with a pressure sensor before worrying about the electronic interface.

In process control industry there are two kinds of pressure sensors, 'transmitters' that send a analog value of the pressure within the sensors design pressure, say 0-5 bars range. The second is a pressure switch that is usually a sensing diaphragm coupled to a switch that changes state when the pressure is below or above the adjustable range of the switch.

So once you decide on the sensor to use then get back for interfacing requirements.

Lefty

 

[mae2007]

Dear thanks for reply
I need the second type which only sense the pressure below or above the value I want

 

[Leftyretro]

Dear thanks for reply
I need the second type which only sense the pressure below or above the value I want

In that case you won't need any comparator electronics as pressure switches outputs just normal switch contacts.

Here is an example of a typical adjustable process pressure switch:

**broken link removed**

Lefty