OK, great. That switch you linked to comes in two flavors. OFF-ON and OFF-MOM (Momentary) That can be worked into the scheme but which flavor will you be using and what DC control voltage? I understand the inclusion of an E-Stop (Emergency Stop Switch). The only issue I see is:
The idea is to use the capacitive switch as the means of latching the relay on or off, so this is the main power switch which also at the same time controls the 12VDC.
Circuits that work like this require constant DC power since you are opting for a capacitive touch switch. You can place a manual On-Off switch on your DC supply but that DC Bus needs power already present to function. Here are your switch specifications:
• Max. current/voltage rating : 200mA 24VDC
• Supply voltage : 5VDC, 12VDC or 24VDC
• Life expectancy : 50 million cycles
• Power consumption non-illuminated : 7mA
• Power consumption illuminated : 25mA
• Operating force : 0N
• LED state for output image option :
1 LED : the LED is ON when the output is closed.
2 LEDs : first colour is ON when the output is open. Second colour is ON
when the output is closed.
• Output type : NPN
Personally I wouldn't go with this switch and here is why:
This switch should not be used
in safety applications.
Anytime an E-Stop is involved you want to keep things as straight forward and foolproof as possible. The switch output type is Open NPN which is like an open collector NPN transistor but they seem to be using an N Type MOSFET. As drawn in the data sheet I don't see any flyback diode protection for the MOSFET? Anyway, when switches like this fail they fail shorted 99% of the time, the MOSFET shorts and unless you have a mechanically latching E-Stop (large red mushroom head with a twist lock normally closed) you are in trouble. This is why the data sheet mentions not using this type switch in any safety application.
When it comes to applications like this I suggest keeping things conventional. You can still have a nice panel and still have pretty LED lamps but keep the relay latching simple just using mechanical switches of the push button type. Thoughts?
Ron