Stop/Start Button & Toggle Button

[tbones]

Hi All,

Can someone tell me the difference between a stop/start button & a toggle button. And why use one instad of the other?

This is in realtion to a SCADA system where the operator will operate a motor out in the field


Thanks

 

[iant]

what happens when you press a start button then press a stop button
(first part)

what happens when you touch the power on button on a TV or remote
(second part)

SCADA - ditto

 

[tbones]

Thanks. Is there any reason why you would use one over the other? or is it a matter of personal preference?

 

[Aabeck]

I found it easier to use a single illuminated pushbutton to toggle a device on/off due to the fact I only have to punch one hole in the cabinet, verses 2 (or 3 for a light) using start/stop. Of course if you're not using a PLC to control the device you pretty much have to use start/stop pushbuttons. Also remember that HMI virtual pushbuttons are "toggle" type.

 

[Tark]

Thanks. Is there any reason why you would use one over the other? or is it a matter of personal preference?

What do you want to happen when power is lost and then turn back on? With Start/Stop buttons the motor will stay off, with a toggle button the motor could turn back on.

 

[Aabeck]

What do you want to happen when power is lost and then turn back on? With Start/Stop buttons the motor will stay off, with a toggle button the motor could turn back on.

I presume that the OP when referring to a "toggle" button means a single momentary pushbutton that triggers a OneShot in the PLC program, that controls a JKFF (or toggle) control of the output.

To me it sounds like a students question.

 

[iant]

Guys
I know that is what the OP is asking

my usual responce is to search the site for FLIP FLOP or Toggle

there are already hundreds of posts
this is a common student question

If we answer this every time we will fill the forum storage.

Like my signature says
GUIDE - NOT ANSWER



\

 

[iant]

Thanks. Is there any reason why you would use one over the other? or is it a matter of personal preference?

it depends on the design of both your machine and or the wiring

 

[Lancie1]

Do not forget that there are physical pushuttons that go ON first press, OFF on second press. Tark pointed out a reason not to use one of these physical toggle buttons. That would apply to a SCADA virtual toggle button also.

 

[LWCiak]

I would be afraid to offer any advice on this subject. Unless one knows the control philosophy of the members question it is impossible to answer.
To many unknowns.
Push buttons versus toggle switches:
PBs can be momentary or maintained.
Toggles can be maintained or momentary.

It all depends on the control philosophy as I mentioned. Safety MUST override convenience.

My 2 cents.

 

[Manglemender]

Another posible reason for the question is legislation.

I don't recall whether it is expressly forbiden or not but using the same button for start and stop should be avoided as the outcome of a button press is ambiguous. This is especially true in cases where switching something on might represet a hazard i.e. starting a motor.

Perhaps the OP can enlighten us as to the thinking behind the question.

Nick