Previous in Forum: To measure Dew Point RH, Temperature & moisture contents of Gaseous Stream   Next in Forum: Speed of sound
Close
Close
Close
11 comments
Power-User
Engineering Fields - Mechanical Engineering - I am here to help!!

Join Date: Apr 2007
Posts: 194
Good Answers: 2

Pressing multiple buttons on a touch panel

12/12/2021 7:59 PM

If I have a touch panel with say 5 buttons, where I am supposed to touch one button at a time and then the next one, how do I prevent any further action after pressing multiple buttons at once.

I mean, pressing multiple buttons should stop any function which, pressing a single button would do.

Is there a standard protocol or a way to prevent this and how reliable is that? Can it be overridden easily or is it a complete fix?

Thanks in advance!

Register to Reply
Pathfinder Tags: Touch panel
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 30958
Good Answers: 1727
#1

Re: Pressing multiple buttons on a touch panel

12/12/2021 9:07 PM

Well I have no idea what you are talking about, but one possibility might be to add another switch that registers your touch button selection, and then has a hold until confirm button that includes a cancel button, that way your one button press requires two buttons, one for select and one for confirmation, or cancel....

__________________
Break a sweat everyday doing something you enjoy
Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 20964
Good Answers: 780
#2

Re: Pressing multiple buttons on a touch panel

12/12/2021 11:34 PM

If the program logic enables it, each button could be put in series with a not on every other button. However, even with that, program scan order and timing might still present further issues.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Guru
Australia - Member - New Member

Join Date: Feb 2008
Location: Australia
Posts: 2131
Good Answers: 251
#3

Re: Pressing multiple buttons on a touch panel

12/12/2021 11:50 PM

This seems relatively simple. The first "button" activated simply sets a lockout timer for any other function.

If you want the keyboard smashers to be able to "interrupt" the original signal, then simply flip it the other way so that "any key" works as the interrupt.

I used to build "lockout" systems for "game shows" (community events, not the TV level ones) and this is simple with even relay logic. modern PLCs or computers would also take that programming logic easily.

__________________
Just an Engineer from the land down under.
Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30314
Good Answers: 817
#4

Re: Pressing multiple buttons on a touch panel

12/13/2021 5:10 AM

It's only a matter of programming. Having defined "what" as above, the "how" goes to a lower level, as there are any number of ways of doing it subject to the organisation's standards and the Designer/Programmer's preference; those sorts of things cannot be seen from here.

If pressing the first button sets in action a sequence of events, then why would pressing any other button be a requirement for that sequence to continue (rhetorical question - NNTR)?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 20964
Good Answers: 780
#5
In reply to #3

Re: Pressing multiple buttons on a touch panel

12/13/2021 9:04 AM

If relay or computer logic were executed instantly, this could be true. But that is not necessarily, or even normally, the case. For instance, aforementioned scan delays, or even mechanical response-time issues, could mess things up. My post #2 hints at the problem, but doesn't necessarily solve it.

I once saw a Jeopardy show in which one contestant's buzzer was not working. She didn't protest, but simply kept pressing her button to no effect.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
2
Guru

Join Date: Dec 2007
Location: Haverhill, MA
Posts: 1146
Good Answers: 149
#6

Re: Pressing multiple buttons on a touch panel

12/13/2021 11:50 AM

Assign each button to one bit of a word:

button A to bit 1, B to bit 2, C to bit 3, and so on

Now evaluate that word as a binary integer

If WORD=1 THEN action A

If WORD=2 THEN action B

If WORD=4 Then action C

And so on

However, if two buttons were pressed , say A&B then WORD would =3 and none of the actions would be selected.

After scaning the list of possible actions and none were selected reset WORD to 0

if action was selected, reset WORD when the action is completted.

__________________
The older I am, the better I used to be
Register to Reply Good Answer (Score 2)
Guru

Join Date: Dec 2009
Location: Land of Shining Waters
Posts: 792
Good Answers: 31
#7

Re: Pressing multiple buttons on a touch panel

12/13/2021 12:09 PM

Various solutions surely. I'm most familiar with relay ladder logic, but whatever the method, your problem needs to be better defined for it to be properly addressed.

- Is it specifically a manual operation? eg: Push first button starts sequence one. Push second button starts sequence two, and so on...

-Can each sequence immediately follow the preceding, or must there be delay from one sequence to the next? Can the sequences overlap or must each sequenced step be complete before the next is initiated?

-If the operator pushes multiple buttons simultaneously or pushes buttons out of order is it necessary to shut down the entire operation or would simply no circuit response to these errant inputs be acceptable?

-What about manual shutdown? One button to shut down everything and/or manual shutdown provided for individual sequences? If so, would shut down of any one sequence cause automatic shut down of all following sequences?

And so on...

__________________
It is easier to let the cat out of the bag than to put the cat back in the bag.
Register to Reply
Guru

Join Date: Dec 2007
Location: Haverhill, MA
Posts: 1146
Good Answers: 149
#8
In reply to #6

Re: Pressing multiple buttons on a touch panel

12/13/2021 1:43 PM

The touch panels that I have worked with, this function is included in the programmig software as the "radio button" function and works as I have described with a PLC.

__________________
The older I am, the better I used to be
Register to Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16498
Good Answers: 661
#9

Re: Pressing multiple buttons on a touch panel

12/18/2021 4:49 AM

Several solution based on hardware, software or both.
Buttons need to be de-bounced either by hardware (resitor capacitor network is the simplest).
If each button has a value e.g 8 buttons one acting on each data bit giving values 1,2,4,8 etc . A read of the data say 50 times a second will show which are being pressed and can prioritise the operations or ignore them as appropriate.
Software could either scan the buttons sequentially and once one is operated, ignore the rest, or work on an interrupt system, once one interrupt is being processed the other interrupts are masked (dissabled).
Failing all that a spring loaded boxing glove should deploy when multiple presses are detected.
Del

__________________
health warning: These posts may contain traces of nut.
Register to Reply
Guru
Philippines - Member - New Member Engineering Fields - Instrumentation Engineering - New Member Engineering Fields - Control Engineering - Who am I?

Join Date: Oct 2006
Location: Philippines
Posts: 2075
Good Answers: 51
#10

Re: Pressing multiple buttons on a touch panel

12/21/2021 9:55 PM

The touch panels I've worked with have that ability built in. When you press a button, it will automatically ignore any other key presses until you lift your finger from the screen.
If your panel doesn't have that ability, you could create one in your PLC. On one rung, connect all the buttons in series (assuming your buttons are NO or normally open) and to a single output instruction (Let's call it ButtonEnable). So, when all buttons are not pressed, ButtonEnable is On and when any button is pressed, ButtonEnable is Off.

Next, add a N.O. contact instruction in series with each button so that if a button is pressed, ButtonEnable will turn off and disable the other buttons. Note that this will result in a pulse instead of a steady On signal from the pushed button. You'll need to add some extra logic if you want a signal that stays On as long as the button is pressed. This suggestion is just to disable the other buttons.

regards,

Vulcan

__________________
Miscommunication: when what people heard you say differs from what you said. Make yourself understood.
Register to Reply
Participant

Join Date: Jan 2022
Posts: 1
#11

Re: Pressing multiple buttons on a touch panel

01/11/2022 11:11 AM

I built an RSView 32 touch display for a museum exhibit and when it was first used, the computer was overloaded by children pushing multiple buttons and I had to redo the PLC program as well as the RSView 32 design to handle this. Over the years, I had multiple computer failures that required replacements and we finally settled on a hardware answer without any computer. Only the PLC 5/60 running it.

The exhibit is a 67 ton 3 cylinder steam engine from a ship running by an electric motor and a VFD.

Original RSView 32 touchscreen.

Register to Reply Score 1 for Good Answer
Register to Reply 11 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

canadianslidewinder (1); Del the cat (1); gringogreg (2); Just an Engineer (1); pattywal (1); PWSlack (1); SolarEagle (1); Tornado (2); Vulcan (1)

Previous in Forum: To measure Dew Point RH, Temperature & moisture contents of Gaseous Stream   Next in Forum: Speed of sound

Advertisement