Security Alarm

I am trying to write plc ladder logic for two-zone home security system. I have 1 momentary PB used both arm and disarm. Another momentary PB for panic. Normally closed toggle for windows & another for entry/exit door.
There is 10 sec entry/exit delay. If at anytime the system is in the arming or armed state & window opened, siren sounds. Arm/Disarm PB will turnoff this alarm and disarm system. If your 10 sec run out before exit or upon entry disarm the siren will sound. Arm/disarm PB also stops this siren and disarms. The oanic can be pushed at any time and siren sounds, arm/disarm PB turns off siren & returns alarm to its previous state. The siren also can sound for 15min (15sec ton) and then will reset itself to armed state pertaining doors & windows are closed. Need help woth my logic, tried many times, and just dont have something right

hohoride said:

I am trying to write plc ladder logic for two-zone home security system. I have 1 momentary PB used both arm and disarm. Another momentary PB for panic. Normally closed toggle for windows & another for entry/exit door.
There is 10 sec entry/exit delay. If at anytime the system is in the arming or armed state & window opened, siren sounds. Arm/Disarm PB will turnoff this alarm and disarm system. If your 10 sec run out before exit or upon entry disarm the siren will sound. Arm/disarm PB also stops this siren and disarms. The oanic can be pushed at any time and siren sounds, arm/disarm PB turns off siren & returns alarm to its previous state. The siren also can sound for 15min (15sec ton) and then will reset itself to armed state pertaining doors & windows are closed. Need help woth my logic, tried many times, and just dont have something right

Click to expand...

Post what you got and we'll try to steer you in the right direction without actually doing the work for you.

Post what you have so far on your logic and as much info as you can on make/model

Security alarm

Ok, you will probably get a laugh from this, but I dont know how to enter my drawing on this site?? Have it on paper and my flash drive. If you can direct me a bit please and I enter what I have. I cant draw and save on this computer, I am at work and dont have any way do that. I dont believe I can transfer from flash either b/c of firewall & unsupported items. (lol) My last day of class is tuesday in which we have PLC access but not internet. This is not a required assignment, i am anout 2-3 labs ahead of others in class was attempting to get this one or the traffic light done. If there is another way I can explain what I have to you, please let me know. It bugs me when I just can't get it!!! I been working on this one 4 class periods. Thank you

Post what you have - if it's paper drawings, scan them. Compile information together in a zip folder and post the zip. That works every time it's tried...

As a rule, we're not going to do your homework for you. Remember, this is information you should have already learned, now you're just reinforcing the book-learning with practice. We'll gladly help guide you through the process, but you're going to have to show us what you already have, ask specific questions, etc.

The first part of any programming project is definition. DEFINE your system first -- how is it supposed to behave? With a system like this, a flow chart works really well. THEN, you can start designing your PLC code.

Security alarm

Oh gosh...Lol, I swear on everything I am not bullcrapping, I do not have access to scanner either so here goes, Ill try write out each rung...
So I will have 2 outputs that will both work on (L) & (U) commands O:3/0 armed/disarm & O:3/3 Siren sounding/off
4 total inputs momentary PB that is both arm/disarm command I:1/0, anothe PB for Panic I:1/1
2 toggles one for door and one for windows I:2/2 & I:2/5
there is 10 sec entry/exit delay and 15sec max alarm siren before reset.
R1 I:1/0 and TON T4:0 w/ 10sec preset
R2 T4:0/DN closed door contact & window O:3/0(L)
R3 O:3/0(armed) open door 2nd TON T4:1 10s
R4 T4:1/EN closed T4:1/DN I:1/0 O:3/0 (U)
R5 I:1/0 closed I:2/2 & I:2/5 T4:0/TT O:3/0(L)
R6 O:3/0 open I:2/2 O:3/3(L)
R7 O:3/3 I:1/0 closed I:2/5 O:3/3(U)& branch O:3/0(U)
R8 O:3/0 panic I:1/1 O:3/3(L)
R9 O:3/3 TON T4:2 15s
R10 T4:2/DN & branch I:1/0 O:3/3(U)
R11 I:1/0 closedI:2/2 & I:2/5 T4:/TT O:3/0(L)
R12 O:3/0 I:1/1 O:3/3(L)
I have like 2 more rungs, but gotta run, lil man got baseball game! be back in about 6am in morning if your available, thanks

Here is a translation of HoHo's description into RSLogix, using the LogixPro Simulator.

I can see several errors. ARM and SIREN are latched and unlatched too many times. Each should be latched once, and unlatched once. Better still, do not use Latch and Unlatch relays, and do use OTE (Output Energize) for ALARM and SIREN.

Another error is the way you use the Arm MOMENTARY CONTACT pushbutton. Because you are using this one pushbutton to perform TWO functions (ARM and DISARM), you must use alternator logic to switch between the two each time that I:1/0 is pressed.

HINT: I posted the wiring diagram for a relay version of this exact security alarm program somewhere on this site about 2 months ago. It was much simpler! EDIT: I can't find it, so maybe I dreamed it.

I dug out the old relay wiring diagram for a simple burglar alarm. Notice that Latching and Unlatching timers and relays are not used.

Security alarm

Wow, thank you. Much Simpler but I dont 100% know how to fully interpret your relay drawing. Our book has couple basic pictures in chapters but they are not discussion topics in lecture. I know I have a bunch of repeats, but the more simple I tried to make the more problems I had, So I went back to long form to quote and came for help from you guys. This is not a homework assignment or required assignment its lab that I started on my own and are trying to finish by tuesday our last day of available lab time.

Security alarm

Looking through some of your notes attached to my ladder logic, ex: on rung 7, your notes say (unlatch siren and arm again!) & yes that is what my rung says, so how would I go about fixing this?? because anything that sets off the alarm except panic when you turn off the alarm it disarms at same time. But if panic caused the siren to sound when you push button or it times out, it goes back to whatever state it was in. That is why I went back to so many seperate rungs because it was dependent on what set off the alarm as to what the PB or timer did.

Hoho,

To write bullet-proof logic, you must learn energize ARM one time in your entire program, and also deenergize ARM one time. Doing ARM and DISARM multiple times will not work very well, as you have found out.

Much Simpler but I dont 100% know how to fully interpret your relay drawing.

Click to expand...

Look how similar it is. All you have to do to make your program work is to duplicate the relay logic in PLC ladder logic. Here is a hint: Relay logic was the original on/off (Boolean logic) on which the RSLogix that you are using in your ladder program was based. Most of the relay logic instructions will translate directly 1-to-1 over to RSLogix. Here are the ones that will not:

(1) Relay logic rung 1, Pust to Start, Push again to Stop. This is a special type of pushbutton, but because your pushbutton was specified by your instructor to be a "momentary contact", then you cannot use the one I show in the relay logic. Instead, you must create alternator (or "flip-flop" as called by some) logic to implement the Push ON, Push OFF function. You can do it on 1 rung, or up to 3 rungs. If you do a search here on PLCtalk.net for alternator, you will find many ways to create this function in RSLogix.

(2) Exit Delay Enabled. This function is needed to seal-in the T1 Timer when it is enabled. In relay logic, most (not all) Timer Relays had no "Timer Enabled" bit, so an extra relay was needed to hold the timer on until it finished timing, but guess what? You do have such a Timer Enabled bit in RSLogix, a very useful timer bit, so you can use that and completely eliminate R1 from the ladder logic. Simply use T4:1/EN in place of the R1 contact, and use T4:3/EN in place of the R2 contact on relay logic rung 2, 3rd branch.

That is all, the remaining instructions will translate directly into RSLogix. Your rungs should have the same branches and connections as shown in my relay logic You should wind up with about 3 ladder logic rungs:

Rung 000: Alternator logic to create the Push ON, Push OFF function.
Rung 001: The logic for the EXIT DELAY Timer T1.
Rung 002: The logic for the SIREN Output, the ALARM DURATION T2 15-minute Timer, and the ENTRY DELAY 10-second T3 Timer.

3 rungs to replace your 12-and-growing-did-not-work program. Is that not a bargain, or what ???

I will test the relay logic in the LogixPro Simulator to make sure that it does work. I did this burglar alarm schematic about 30 years ago for a friend, built the control panel, and he installed it in his mother's home, and said it worked great. But I had to redraw it from memory, so maybe I forgot a few things. I will test to see. In the meantime, you could be working on your new ladder program. Please forget the old one, it is not worth fixing!

Looking through some of your notes attached to my ladder logic, ex: on rung 7, your notes say (unlatch siren and arm again!) & yes that is what my rung says, so how would I go about fixing this?? because anything that sets off the alarm except panic when you turn off the alarm it disarms at same time.

Click to expand...

You are making it more complicated than it is. Look at the relay logic that I gave you. It has all the basic functions that you need. You need these:

(A) Exit Timer to allow time to close door after setting alarm,
(B) Entry Timer to allow time to cross room and hit the ARM/DISARM pushbutton before alarm goes off,
(C) Alarm Duration Timer to control how long the alarm sounds once it has been tripped.
(D) a Siren Output. I used O:2/3.
(E) Alternator logic to allow pushing button once to arm, again to disarm. I did this on the first rung, using a one-shot and a latch and unlatch relay!

There is a sequence to the alarm operation:
(1) Close doors and windows.
(2) Push ARM button.
(3) Exit Timer starts and seals itself on so that it will not drop out until DISARM is pushed. Use the DONE contact from this Exit Timer as your Armed relay. You do not need another, and you certainly do not need to use a latch. Using a latching relay here will make the program very complicated and not as reliable as a plain old seal-in contact on the timer.
(4) Leave house before entry timer is DONE.
(5) Alarm is armed and active. If the door is opened, the Entry Timer starts and times to 10 seconds. If the DISARM button is not pushed withing 10 seconds, the siren goes off. When DISARM is pressed, the Exit Timer drops out and you are back to the DISARMED mode.
(6) Panic mode is a special case (see below).

But if panic caused the siren to sound when you push button or it times out, it goes back to whatever state it was in. That is why I went back to so many seperate rungs because it was dependent on what set off the alarm as to what the PB or timer did.

Click to expand...

An alarm Panic Button normally works like this: Your old granny is in bed one cold night, with her security alarm in ARMED mode. She hears someone trying to jimmy the door lock. She pushes and holds down the Panic Button near her bed. The alarm siren goes on immediately (no delay) and stays on as long as she holds her finger on the button. When the prowler runs away, granny releases the button and goes back to sleep. The alarm is still in armed mode and will go off if someone trips one of the door or window sensors.

I have converted the relay logic to RSLogix ladder rungs. There was one small problem in connecting the wire from the Alarm Duration Timer to the Siren. Relay logic is very flexible, and there are connections you can make with relays that cannot be done in ladder logic. So you have to work around the programming limitations. I had to add another rung to solve that branching problem, so now have 4 rungs that work like a sewing machine. I even added a little something extra, an ARMED INDICATIOR LIGHT that flashes during the entry and exit delays, then goes on solid to show that the alarm is armed.

If you will post your progress so far, we can work though this thing and get it done by your Tuesday deadline.

Security alarm

Alrighty, I'm on it. Will be back when I have my new logic. Thanks for being patient with me, this whole semester I have had the problem of making things more difficult than they really are. Don't know how many times my instructor has told me that, and with a little help it usually clicks. Maybe same luck here. And thanks may nned you showme how to make the light flash as output but that is part of the instructions

I see you are working on your program. Questions?

Security alarm

ok for first rung

I:1/0 Mom PB-----OSR---------Closed contact O:2/0(armed) & (L??) B3:0/2, and then branch w/ open contact O:2/0 (disarm) & (U??) B3:0/2????