Pause/Resume

[ielkhatib]

Sometimes in a specific Project I need to disable all the output of the system, Then I can Resume it again by Pushing The Same Button ( Pause ) or by pressing another button ( Resume ), In Delta PLC There is a special marker that does the trick ( m1034 ) but in Other PLCs I have to program it,
Pausing is actually Stopping so it's easily done before outputs to put a NC contact of Pause_PB .. But when I wanna Resume the outputs on the same Sate before pressing the button << How can I Do that In Ladder Diagram ??

 

[ganutenator]

I did this in the SLC AB back in the day.
It was a long time ago.
I think I disabled calling the subroutines?
I used it to single step the program to figure out some stuff.

 

[parky]

Sometimes you need to do it in a controlled manner, for example, if you have a process where you are pumping product into a tank stopping a pump & closing valves at the same time can cause high pressure in the line as often a pump will carry on well after the valve closes. I produce a task process where you can start it, hold it, resume it & abandon it.
I use an integer to control the task status & control so for example:
IDLE = 0
Start = 5
Open Valves = 10
Start pumps = 15
Running = 20
Hold = 25
Hold on Exception (Alarm) = 30
Resume go back to 5
Abort = 35
I compare the integer & make it equal flags for the modes.
You can add as many states as you wish perhaps use time delays for each stage (to stop pumps before close valves etc).
Use the flags to disable the outputs.
You only have to write a function once & use it many times for different tasks. I call it a Task engine. it makes for graceful shut down of a process.

 

[ielkhatib]

Sometimes you need to do it in a controlled manner, for example, if you have a process where you are pumping product into a tank stopping a pump & closing valves at the same time can cause high pressure in the line as often a pump will carry on well after the valve closes. I produce a task process where you can start it, hold it, resume it & abandon it.
I use an integer to control the task status & control so for example:
IDLE = 0
Start = 5
Open Valves = 10
Start pumps = 15
Running = 20
Hold = 25
Hold on Exception (Alarm) = 30
Resume go back to 5
Abort = 35
I compare the integer & make it equal flags for the modes.
You can add as many states as you wish perhaps use time delays for each stage (to stop pumps before close valves etc).
Use the flags to disable the outputs.
You only have to write a function once & use it many times for different tasks. I call it a Task engine. it makes for graceful shut down of a process.

Thanks parky, I Actually got what you mean, but Um having a little trouble Applying it, Can you Send me an Example of this that you might done before on a project in a pdf format or smth ?

 

[parky]

Here is one, the first 8 segments are of the task control, it has not been written in a function block but in the main FBD. This is only a test program I did for somebody to demonstrate it, there is a simulation code as well. the idea is to show how the task controls certain bits i.e. hold motors, & hold valves & the logic so you can only abort if in hold, only resume if in hold only start if idle.
This was done in GXWorks for Mitsubishi but it would just be a matter of converting it into what ever plc you use, as I say you only need the 8 segments as the others are for demonstration of using a sequence word for the steps of control.