Control panel indicators.

[sparkydude]

Hi just a quick question here, i have to make a small control panel which will have a N/C contactor which will open by the use of a keyswitch to test the batteries of a charging unit. The consultants have asked for a power on indicator from the two supplies operated by the contactor, which is fine, they will simply be supplied by the circuits inside the box. Their will also be an indicator which will only illuminate once the keyswitch has been operated to indicate that the system is on test. This is all great but now the consultants have thrown a lamp test button into the mix, so i am wondering what is the logical function of this test switch. Would you normally turn off lamps that are normally on to test them , or would you just turn on lamps that are normally off .
The lamps are going to be LEDs anyway but just wanted to know your thoughts on this .

Nick

 

[UNG]

IMO all the lamps should be turned on to test them even those that are on all the time. There is no confusion then as to what is working and what is not

 

[Knobhead]

Definitely turn on.

 

[grantr37]

send me your email address with what you are looking for, I will design you a circuit and write you a list of parts from maplin or RS to use to build it......maybe you would want the "on test" LED to flash on and off in order to allow the user not to forget that the unit has been switched from "on" to "test only" and for a few pennies worth of components, you could make the panel beep in test mode as well....the LED's could all illuminate in sequence as well, LED1 for a few seconds, followed by LED2 for a few seconds, then LED3 for a few seconds...all the while beeping until the key gets turned back round to "on" again....don't forget to get some stickers made up to tell the user about turning the key and the lamp test sequence....using some 7400's and a few 555's should do the job (of course with other components).....are you building a small panel (mini size) or fitting inside the existing metal panel/case?

 

[Knobhead]

Why would you use a switch for the lamp test? A simple push button will suffice, it then can’t be left in the test position. A push button is what Sparky has been asked to provide.

The more whistles and bells you fit the more unreliable the lamp test becomes. It needs to be as simple as possible.

 

[johnboy6083]

all lamp test systems ive ever seen, are all push button, hold for on, release for off. no messing about, and no way that it can be left on.
really simple to wire, take a feed from the control circuit, take it through the push button and then loop it through the lamps.
obviously all lamps need to be taken from the same circuit, or else a relay would have to be used, but most sytems i work on have a sincle 110v control circuit.

 

[Knobhead]

If you use a PB with stackable contacts there’s no need for a relay. Telemecanique, Cutler Hammer and others do them.

 

[alarm man]

a 3 position keyswitch will keep it simple one way to test the batteries the other way to test the lamps,nice and simple no need for extra buttons then

 

[silva.foxx]

Simplicate not complicate. If the control supply is DC then perhaps supply all leds via diode terminal blocks (two diodes with common out), then apply the test supply to the led supply of the diode TB. Applying test voltages to leds has to be done so without actuating anything it shouldn't. If the led is in parallel with a contactor, for instance, then applying a test voltage to the led may also energise the contactor.

 

[nil26]

I think, turn on lamps. Because, all lamp test systems have all on, off and push button. Control panel is used for controling the distribution of energy. They are normally used in industry.