Hi all,

I hope you all doing well. I am struggle to work out how to control 6 pneumatic solenoid valves using PLC to operate one at time, while the remains must stay off and I wanted to start up with a latching circuit where I START/STOP THE PROCESS IN ANY TIME.
What I have done as follow:
first I create a Rung that check all five are off. IN Away: solenoid1 close AND solenoid 2 close AND solenoid 3 close AND ..... SOLENOID 5 CLOSE and the output to check all solenoid are off.
In the next rung I have choose solenoid 1 to be open. In away :
Solenoid 1 open AND solenoid 2 close ........ solenoid5 and the output is solenoid 1

Thanks in advance

 

There are many things that need to be included here. I want to post some questions:

1. Why do you need to check if all solenoid valves are off?
2. If one solenoid valve is open, what happens to the output of these logic (the one checking for "OFF" position)? Is it connected to somewhere else?
3. How do you intend to latch the output of each solenoid?
4. You mentioned one at a time. Does this mean you only intend to open/close just one then lock others?
5. If one valve is open, your intention is not to open any closed solenoids until the one you opened is closed?
6. Are you using an I/O to open/close or just a memory register?

You have to clearly state your intention on doing your experiment (if we may call it that way). You can also mention the PLC that you are using.

 

Hi Superbullet,
Thank you for taken the time to write this for me.
Why do you need to check if all solenoid valves are off? - To make sure all of them are in off state as it must be normally close.
If one solenoid valve is open, what happens to the output of these logic (the one checking for "OFF" position)? Is it connected to somewhere else? - All of them is connected to different boiler but we need to fired in desired boiler and if any thing went wrong, to ensure only active safety valve is open on the boiler being tested.
How do you intend to latch the output of each solenoid? -I just wanted to find a way that to move for each one of them and I do not want to use timer as the purpose is for testing.
You mentioned one at a time. Does this mean you only intend to open/close just one then lock others? -Yes , I only wanted to open one at time and make sure other are remains locked.
If one valve is open, your intention is not to open any closed solenoids until the one you opened is closed? - Yes that is true.
Are you using an I/O to open/close or just a memory register? - I am using an I/O and I am using IDEC PLC.

I hope I do answer your questions.

 

Hello Soma,

Attached is a basic ladder logic for your system. Please take note that this is a simple logic and you need to make it more robust for your application especially the SOL1...SOL6 that needs to monitor your solenoid valves (feedback) if close or open. S1...S6 is the output going to the solenoid valves. I1.1/I1.2 (NO switch)...I6.1/I6.2(NC switch) are true I/Os or memory registers (depends on you). Some PLCs can activate 1 pushbutton for close and open (Allen Bradley has it). One push to energize and another push to de-energize. SOL1...SOL6 can be NO or NC. You can make the logic simpler. Goodluck!

 

Hello Superbullet,

Thank you so much for your help. Your guidance and expertise were invaluable. I really appreciate you taking the time to walk me through these steps.

 

Hello Sona,

Does this mean it is working? If you need more explanation, just reply to this thread.

 

I haven't tested yet, only the simulation. Once it all wired I'll let you know.
Thanks again