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Old May 6th, 2013, 03:19 PM   #1
Nova5
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Alarm Horn Manual Silence, Auto Reset.

Looking to silence an alarm from a HMI Button. Right now the HMI button command is set to Pulse the binary bit.

Will the attached logic work to silence the alarm but allow the light to remain on?

When the program starts no alarms should be present (supposing the system is properly primed) Temps will be in range, HH's will not be in alarm state. As the Start permissives require that to be correct.

Any Alarm going High in logic will set the Alarm Light+Horn to True.

So the Alarm Light Output should be TRUE on the NC switch(due to false in the referenced input), ONS sees the False/True transition, allowing the rung to go true, Latching Alarm Horn Silence Logic Bit. which will allow alarms to trigger the horn.

Next when/if the Alarm Horn Silence HMI button is pressed that run goes true and unlatchs the Alarm Horn Silence Logic Bit, silencing the alarm.

The button on the HMI is only visible and usable when an alarm has triggered the Alarm Light/Horn.

When the alarm(s) clear, the light goes false and the corresponding NC contact on line 2 goes true, latching the horn logic bit for the next alarm to successfully call for the horn.

I'm a little new at this so my explanation may be a little rough. The attachment is just from a clean program So i could look at it without affecting my actual program.
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File Type: jpg Alarms.jpg (21.0 KB, 179 views)
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Old May 6th, 2013, 08:47 PM   #2
iant
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do you need to use latching relays?
I am assuming you are a student - sorry if I am wrong
write a truth table for the actual control.
Normally we would reffer to this as a 'MUTE' cct
so
1. b3:0/2 is off ONS - B3:0/5 latches on
2. toggle ON b3:0/1 'ON'
3. b3:0/2 turns on
4. b3:0/5 is on b3:0/3 turns on
5. b3:0/4 is toggled ON - b3:0/5 turns off
6. system now waits for a status change
what is b3:0/1 and b3:0/4
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Old May 6th, 2013, 09:04 PM   #3
yang1216
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try this:

XIC B3:0/1 BST OTE B3:0/2 NXB XIO B3:0/5 OTE B3:0/3 BND
BST XIC B3:0/4 NXB XIC B3:0/5 BND XIC B3:0/2 OTE B3:0/5
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Old May 6th, 2013, 09:08 PM   #4
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Quote:
Originally Posted by yang1216 View Post
try this:

XIC B3:0/1 BST OTE B3:0/2 NXB XIO B3:0/5 OTE B3:0/3 BND
BST XIC B3:0/4 NXB XIC B3:0/5 BND XIC B3:0/2 OTE B3:0/5
sometimes an answer like that is not the best way to help.
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Old May 6th, 2013, 09:20 PM   #5
Ron Beaufort
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not sure if this is what you're looking for but there are some ideas for basic alarms in the attached file ... it was written for an SLC-500 platform but should be easily modified for anything else ...

basic ideas:

each field signal gets three separate timers ...

(1) you get to tweak the first timer to determine how long each signal can be "out of tolerance" before you consider the field input signal to be in an "alarm state" ...

(2) you get to tweak the second timer to determine how long each signal must be back "within tolerance" before you consider the "alarm state" to be cleared ...

(3) you get to tweak the third timer to determine how long an alarm state may be silenced before the horn turns back on again to remind (nag) the operator that an "alarm state" still exists ...

so ...

whenever a "new" alarm state is declared, a horn sounds and a beacon lights up to alert the operator that an alarm condition exists ...

the operator can press the "silence" button in order to concentrate on correcting the condition so the horn turns off but the beacon stays on ...

if the condition doesn't get corrected in a timely manner, the horn sounds again to remind the operator that something still needs to be done ...

naturally some field conditions require very prompt attention ... others can go quite awhile before things get serious ... and some operators might just press the silence button repeatedly and go right back to sleep ... the basic ideas in this program give a lot of flexibility in how different types of "alarms" are handled ...

.
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Old May 6th, 2013, 09:23 PM   #6
Nova5
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Quote:
Originally Posted by iant View Post
sometimes an answer like that is not the best way to help.
I can drop it into RSLogix Micro Std and it'll build the line.

No, not a student. Just very new at it. Latching would seem to be a way to ensure it can hold its state.
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Old May 6th, 2013, 09:27 PM   #7
Nova5
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Quote:
Originally Posted by yang1216 View Post
try this:

XIC B3:0/1 BST OTE B3:0/2 NXB XIO B3:0/5 OTE B3:0/3 BND
BST XIC B3:0/4 NXB XIC B3:0/5 BND XIC B3:0/2 OTE B3:0/5
That should work just fine. simple change to my logic that I should have spotted, latched plenty of outputs that way in the program.. ahh mental vaporlock...

Last edited by Nova5; May 6th, 2013 at 09:33 PM.
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Old May 6th, 2013, 09:31 PM   #8
Nova5
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Quote:
Originally Posted by Ron Beaufort View Post
not sure if this is what you're looking for but there are some ideas for basic alarms in the attached file ... it was written for an SLC-500 platform but should be easily modified for anything else ...

basic ideas:

each field signal gets three separate timers ...

(1) you get to tweak the first timer to determine how long each signal can be "out of tolerance" before you consider the field input signal to be in an "alarm state" ...

(2) you get to tweak the second timer to determine how long each signal must be back "within tolerance" before you consider the "alarm state" to be cleared ...

(3) you get to tweak the third timer to determine how long an alarm state may be silenced before the horn turns back on again to remind (nag) the operator that an "alarm state" still exists ...

so ...

whenever a "new" alarm state is declared, a horn sounds and a beacon lights up to alert the operator that an alarm condition exists ...

the operator can press the "silence" button in order to concentrate on correcting the condition so the horn turns off but the beacon stays on ...

if the condition doesn't get corrected in a timely manner, the horn sounds again to remind the operator that something still needs to be done ...

naturally some field conditions require very prompt attention ... others can go quite awhile before things get serious ... and some operators might just press the silence button repeatedly and go right back to sleep ... the basic ideas in this program give a lot of flexibility in how different types of "alarms" are handled ...

.
Immediate attention alarms bring the system to a halt and alarm for attention. Others just alarm for attention.
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Old May 6th, 2013, 09:51 PM   #9
Ron Beaufort
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Quote:
Immediate attention alarms bring the system to a halt and alarm for attention. Others just alarm for attention.


certainly - and once the basic "alarm" bits are latched on, you could then do whatever is necessary to stop the system or just to call for attention or to do anything else required ...

the part that most people miss when setting up alarms is that SOME conditions need immediate attention but other conditions can easily "wait awhile" before considering the situation to be an "alarm" in the first place ...

many alarm programs just lump every type of condition into one basket with no easy way to accommodate various degrees of seriousness ... having the separate timers allows a lot of flexibility that some other alarm programs don't offer ...

it's just a suggestion ... if your system doesn't require this degree of control then feel free to ignore the suggestion ...
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Old May 6th, 2013, 10:32 PM   #10
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Small process skid. Doesn't need any complex alarming methodology. My statement was more how I have it configured vs anything else.


HMI will display active alarms.
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