screen picture/shutdown alarm?

I am trying to write a program with a delay oil circuit. I did recieve some examples and they where very helpful? However I have drawn a latching circuit with all of my safety shut downs. However when my motor shuts down my oil pressure eventually falls causing my pressure alarm to activate, no need for the alarm now motor not running. I wanted to include a pic of my programming so far but cannot fiqure out how to get it to this screen. I am using direct soft, plc 05 with a c more micro touch screen. Goes without saying just a novice.
Thanks

Just put in logic on your Oil Pressure alarm circuit that enables it only when the motor is running...You'll probably need to delay it a bit too to allow the system to pressurize after turning the motor on. Assuming your Oil Pressure Input is ON when you have pressure it would be something like:


XIC Motor and XIO Pressure Input -> Turn on Timer

Timer.Dn -> Latch Alarm

That says that after X time, the Pressure Input should be ON. If it isn't then alarm. When the motor is turned off, the timer will never time, so you again won't get the alarm.

Thanks, I am really not clear on what you are saying sorry. I start the 25sec oil timer on a signal when my motor starts already? I have my timer contacts in paral with my ops. Then in another rung when/if ops opens I send a signal to v2000 which sends a look up text to my display "low oil Pressure" ???
Thanks

Yeah, that won't work because as you see when the pressure switch opens, you get the alarm.

I'll try to show you the ladder here, but it's hard with formatting:


...MOTOR......OPS
---||---------|/|-----------TIMER 25Secs

...TIMER.DN
---||------------V2000

The rungs say if my motor is running and I don't see the OPS for 25 secs, then alarm.

This assumes that even during steady state you can withstand loss of pressure for 25 seconds. If you can't and need to immediately alarm once the pressure switch makes the first time, then you'll need to do the following instead:


...MOTOR
---||-------------------TIMER 25 Secs


...TIMER.DN.....OPS
---||-----------|/|----------V2000

This says that wait for 25 secs once the motor starts to even look at the OPS. If after 25 secs the OPS is not made, then alarm. Once the Motor stops, The Timer.DN bit goes low and you won't get the alarm.

Lastly, if you can withstand some time of no pressure during steady state running then you can modify the above like this:

...MOTOR
---||-------------------TIMER 25 Secs


...TIMER.DN.....OPS
---||-----------|/|----------TIMER2 5 Secs

...TIMER2.DN
---||-----------------V2000

Here is the first part of my logic. Does it help?

You really should create seperate alarm bits and not use the Input and the Timer Not Done in parallel on your start latch like that.

Use XIO of each alarm bit as your permissives that would break the latch of your start bit.

Each alarm bit would be generated with the logic similar to what I explained above. You should latch them in with some means to unlatch them so your message is maintained until the operator acknowledges the alarm.

...T1.....X2.............C3.........C2
---||----|/|-----+--|/|-----(out)
........................|
...C2..................|
---||-------------

Where T1 = Motor on for 25 secs, X2 = OPS, C2 = OPS Alarm, C3 = ACK PB

Then, your start circuit would use C2|/| in series to break the latch instead of your X2 and Timer in parallel. Do the same for your other faults.

Thanks for the help. I can tell this is very simple for you but I just can not understand what you are telling me to do. My lack of experience!
What you are saying sounds exactly like what i need. What do you mean seperate alarm bits? what do you mean "use X10 of eash alarm bit as your permissive that would break the latch of your start bit" I have tried to reproduce what you sent but it did not come close to working I am sure it just my not understanding your instructions. Also you looked at the pic of what i have done i think you are telling me i am not even close? Thanks for the help

Can you post the oil circuit logic you already have as a pdf or something rather than a screen shot, my eyesights getting bad!

Not X10, but X I O (Examine If Open) or commonly denoted as
-|/|-....

The alarms should latch in otherwise when the condition clears then the alarm goes away and you won't know why the process stopped. It should take an operator action of using an Acknowledge PB to clear the alarm and re-enable starting again.

As an example, in your original code, if oil pressure dropped, the process stops, but because the process stopped, the oil pressure alarm goes away. You have no idea what caused your process to stop in the first place.

Here's an example written for a Siemens 505 series processor using Softshop. I don't have DirectSoft, but the code is somewhat similar (timer block is a little different) but it should give you an idea:

sas11,


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You can then print your ladder with the software, select "Cute PDF" as your printer and you will get the file you can attach to your message,

Hope this helps!