Neon indicator isolation

[meow2222]

Any resistor can arc if V spec exceeded. Carbon comp is not needed for 400v. Even little 0.3w C film are rated 200v.

NT

[Andy Dingley]

I'd probably go with a cheap 16x2 LCD display and write messages on it. Wit h small LED mimics if I needed individuals. This isn't rocket science to bu ild and it allows me to use simple serial cabling, rather than 19 mains run s. Then I can put the status box (and its simple mimics) somewhere I can se e it, not down in the pump room.

I can't imagine much control gear that would have 19 mains signals within o ne box. If I did have something like that, I'd probably be using 48V instea d and almost certainly a PLC as a controller. If I had 19 mains signals ou tside the box, I'd probably either be controlling their mains at the pump r ather than inside the control box and very likely I'd be running a 48V (or current loop, or I2C) back to control.

Big boxes of mains level logic are obsolete. With 19 circuits involved, tha t's so obsolete that it's easier to get a bit more up to date and control f rom a lower voltage.

[Rick Hughes]

Yes agree - I'd like this all done via logic ccts and differently ... if I had it via software ... but but it is already in place, the controller boards with mains relays is there, as are the 13 zone actuators ... and I can pick up the 220V signals form each relay / switch.

As these valves are all 220V ... I would have to either changes a whole load of plumbing (expensive) or add a lot of signal sensors.

This system is in and works (and has been working for a number of years) ... all I'm doing is adding indicators .. so in the event of an issue I can tell what is going on quickly.

[Andy Dingley]

In which case I'd probably go to a rack of optoisolators, then go to LEDs. (Or an Arduino/AVR, serial link, then a remote indicator box). Just wiring up that many mains indicators in a small box is enough of an expensive PITA.

BTW - cheapest way to buy wire-ended neons is to buy mains indicators from China and desolder them.

[Rick Hughes]

Not really ... all neutrals are common ... so that is simple ... the panel will fit alongside the control panel, which already has all the mains signals on a connection terminal strip.

Very simple & quick to hook up ... as mentioned elsewhere I'm using

12way 2 part pluggable choccy block ... so I can remove completely display portion (lid of box) should I need to without disturbing wiring.

I appreciate what you have said .. but optoisolators, LCD panels, software is just too much for what I want ... just a simple on/off illumination.

I'm surprised I have not had someone suggest a Raspberry Pi (or angle grinder)

[Rick Hughes]

This is what the manufacture of the Underfloor Heating system provide ... so that is what is installed ... it may be 'old fashioned' but it works. Even if control system board was changed out .. would still have 17 220V zone actuators, relays for the 3 pumps, thermostat switches & main flow valves ... so this 'old stuff' would still be there.

[Rick Hughes]

Found plenty of Carbon Comp on eBay ... but I will see if I can find sensible source for those Vishay units (do you know of one )

[meow2222]

More complication, more cost, less reliable, less long lived, & impractical to repair in 20-30 years time.

NT

[Andy Wade]

Any of the mainstream distributors - RS, Farnell, CPC, Arrow, Rapid, etc. - will stock VR37 or an equivalent,

[Dave W]

On Sun, 09 Feb 2014 18:42:06 +0000, Rick Hughes wrote: '

If it's "very simple & quick to hook up", why haven't you done it already rather than post here? (I'm being sarcastic).

[Rick Hughes]

On 13/02/2014 16:16, Dave W wrote: ised I have not had someone suggest a Raspberry Pi (or angle

I have done now :-)