Possitive edge inputs with OR gate

manin · Mar 1, 2016

Hello, is it possible to have positive edge inputs in OR gate?

I have 8 inputs and want to trigger Y0, be able to turn off Y0, even if input that triggered is still on..That's ok so far
My problem, is that if another input is being triggered, Y0 must be ON again...

I used positive edge inputs, but simulation does not work that way..

Thanks a lot

daba · Mar 1, 2016

I don't know what PLC hardware you are using, not recognising the "Y0" reference, but no, you will not be able to develop an "OR" strategy if you use "edge-triggered" inputs in your program.

Years ago I worked on a Telemechanique PLC that had "static" and "edge-triggered" instructions.....

---| |---- "is it on" ? = a static instruction.

---|/|---- "is it off" ? = a static instruction.

or

---|^|---- "has it just come on" ? = an edge-triggered instruction.

---|v|---- "has it just gone off" ? = an edge-triggered instruction.

Neither of the latter two instructions will be useful in detecting a logical "OR" condition.

JeremyM · Mar 1, 2016

Obligatory: Need more info!

I suppose you could start by accompanying each OR condition with a one shot, sealing in the output, I suppose:



|---|-------|IN01 |---ONS---------------| ORBLOCK01 |----------------------------------------( OUTPUT01 )

|   |                        |                         |

|   |-------|IN02 |---ONS----|                         |

|   |                        |                         |

|   |-------|IN03 |---ONS----|                         |

|                                                      |

|----------| OUTPUT01 |--------------------------------|

the other condition, ORBLOCK01, can consist of another set of OR statements consisting of the permissives you require and the |\| of each OneShot bit

ostensibly, I see new edge-triggers re-energizing the rung

manin · Mar 1, 2016

daba said:
I don't know what PLC hardware you are using

I am using Fatek Fbs. Y0 is output 0...I thought that most of manufacturers has Y as outputs.

The triggered instructions are like the one you described

OK...
I have 8 inputs. If one of them is ON then Y0 (siren) is ON.
The user must have the ability to turn off Y0, even if input is still ON.

Now if Y0 is turned off by the user, but input is still on, and another input goes ON, then Y0 is ON again...This is the part I am confused...

I didn't understand your thinkning with ORBlocks

osmanmom · Mar 2, 2016

use 1 input

manin · Mar 2, 2016

I used this way...It is not the best code, but it does it's work...
If you have any ideas, feel free to share



|---|-------|IN01 |-------------------------------------------( MEMORY01 )

|---|-------|IN02 |-------------------------------------------( MEMORY02 )

|---|-------|IN03 |-------------------------------------------( MEMORY03 )



|---|-------|MEMORY01 (Pos. Edg)| ------------------------( MEMORY010 (S) )

|---|-------|MEMORY02 (Pos. Edg)|-------------------------( MEMORY020 (S) )

|---|-------|MEMORY03 (Pos. Edg)|------ ------------------( MEMORY030 (S) )





|---|-------|MEMORY01 (Pos. Edg)| 

|---|-------|MEMORY02 (Pos. Edg)|--------OR--------------( Y0 )

|---|-------|MEMORY03 (Pos. Edg)|

amberman · Mar 2, 2016

Jeebs · Mar 2, 2016

Why use different pos edges?

manin · Mar 2, 2016

amberman said:
|---[in01]--[pos edge]--|--------------------[set y0]--|
|---[in02]--[pos edge]--|
|---[in03]--[pos edge]--|
|---[in04]--[pos edge]--|

|---[ack pb]-------------------------------[reset y0]--|

Do you mean OR gate with pos edge inputs?
It does not work

Jeebs said:
Why use different pos edges?

What do you mean?

Jeebs · Mar 2, 2016

Like this?

Code:

|---[in01]-|-[pos edge]----------------------[set y0]--|
|---[in02]-|
|---[in03]-|
|---[in04]-|

|---[ack pb]-------------------------------[reset y0]--|

If that doesn't work:

Code:

|---[in01]--------------|------------------[MEMORY01]--|
|---[in02]--------------|
|---[in03]--------------|
|---[in04]--------------|

|---[MEMORY01]--[pos edge]-------------------[set y0]--|

|---[ack pb]-------------------------------[reset y0]--|

amberman · Mar 2, 2016

Jeebs said:
Why use different pos edges?

If one input remains on and another input goes high it is still detected.

amberman · Mar 2, 2016

manin said:
Do you mean OR gate with pos edge inputs?
It does not work

Yes I mean that - it works with Allen Bradley but not all PLCs handle edge detection the same. I've never heard of a Fatek PLC!

manin · Mar 3, 2016

amberman said:
If one input remains on and another input goes high it is still detected.

I simulated in Fatek and unfortunately it didn't work.

amberman said:
Yes I mean that - it works with Allen Bradley but not all PLCs handle edge detection the same. I've never heard of a Fatek PLC!

That's good to know...I just installed component workbench to practice with it.

Guys, thank you all for your help!!!

Possitive edge inputs with OR gate

manin

Member

daba

Lifetime Supporting Member

JeremyM

Lifetime Supporting Member

manin

Member

osmanmom

Member

manin

Member

amberman

Member

Jeebs

Member

manin

Member

Jeebs

Member

amberman

Member

amberman

Member

manin

Member

Similar Topics