Water Controls

[chris_j_hunter]

>pulse count ...

the other issue, maybe, is how to connect the Idratek module to these valves ... ie: how long can the cable be, and what type ?? ... would be handy if one module could control several taps (in one room, with cable runs up to three metres, say) ... our bathrooms would have maybe five valves to be controlled, and maybe eight in one case (which doubles as a laundry room), plus there's the kitchen ...

it's tempting to use valves without sensors in some places, to save costs, though it might lose some HA options, so not sure !

[Karam]

I should imagine a timed pulse should be sufficient if no feedback sensing is used. Both Cortex and Reflex implement a timed pulse feature where the user can set the duration to within sub second resolution if desired.

If feedback is required then I'm sure it'll be possible to accomodate this in one way or another or if necessary create a specific object to handle it as its reasonably generic.

Regarding powering of valves I think the 24V option + QRIs would probably be the way to do it (don't like 230V near water - even 24 might need some consideration, but 6 not). I haven't seen the valve specs. but you'd have to look at current consumption to work out how many could be strung on to one supply and also whether, like the RVAs, several could be hung on to one CAT5 cable (say) with switched power being at other end. I can't imagine any problem with 3 meters. Only thing I'd recommend with solenoids is fit suppressor at solenoid end.

Karam
IDRATEK LTD

[chris_j_hunter]

timed pulse could be good - just need valves, not valves with sensors ... less expensive & less to go wrong ... OTH, with pressure variations, on the water side of things, due to mains variations or other usages in the house, the timing could be invalidated ... so, I think, my feeling is that feedback must be necessary ...

'bit like X-10, no feedback is fine if things go as expected ... but how good is X-10, in-practice ... not good-enough !

so, do we go buy all those valves, with sensors ... can / will Idratek do the necessary ... ??

[Karam]

Looking at the datasheets for the Betavalve units it would seem that the pulse rate (pulses/litre) depends non linearly on flow rate (litres/minute). Also there is a fair size tolerance band at lower flow rates. It may be possible to use the graph to linearise the data (if the graph is accurate rather than just an indicator) but obviously not much can be done about stated tolerance other than try operating at high flow rates.

In theory an onsite calibration factor can be used to minimise the tolerance uncertainty at usual pressure conditions (ie. at a given flow rate) and then if pressure (and hence flow rate) changes do occur it may be possible to detect and use the change in pulse rate to work out an approximate correction.

Would it be possible to do this with IDRATEK hardware/software? I think so but probably would consider either enhancing the existing pulse counting firmware or perhaps dedicate a digital I/O unit to the task. Not certain yet on the task distribution between Cortex and hardware but I'm pretty certain a new Cortex object or sub object would be required.

Is it worth doing this? I don't personally know since I have no data about the accuracy of the non feedback methods in practice - though I'm told that these are widely used. If anyone has any such information to hand or has time to research it then we'd be pleased to learn.

Otherwise, to answer you're original question, we always like a challenge ;-) so probably try to do it anyway even if small number of requests. But, unless we get a deluge of requests, timing will be at the mercy of other priorities.

Karam
IDRATEK LTD

[chris_j_hunter]

thanks, quite understand the problem - ie: your priorities conundrums !

'thought I'd try some sums ... looking at the datasheet, linearity starts at about 7 litres/minute, about 120ml/sec, and maybe reasonable linearity starts at about 3 litres/minute, about 50 ml/sec ... a cup or glass holds about 250ml, a breakfast-cup about 330ml ... filling one in one or two seconds sounds about right ... ie: we could think in-terms of 10 litres/minute, about 165ml/sec, as being good for filling small things (no surprise, maybe, 'cos probably that's what these valves are mostly used-for) ... at which rate a bucket might take 90 seconds to conveniently-fill (ie: not to the brim), which might be OK (if automatic, 'though might be tempted to use two valves), and a bath (assuming 1.5m x 0.5m x 0.25+m = say 200 litres) might take 20 minutes (could still be OK, if automatic, especially as likely to be quiet, 'though again might be tempted to use more than one valve) ... ie: we probably are talking being always in the near-linear range, at about 600 pulses per litre ... ie: about 1.5 seconds & 150 pulses per cup / 90 seconds & 900 pulses per bucket / 20 minutes & 12000 pulses per bath

might want something less, maybe 5 litres/min', for washing hands, but then we wouldn't be so fussy about accuracy ... or maybe it could come at 10 litres/minute in one-second pulses ... ?

using quad-button module, might have one button for hand-wash, another for a cup, another for a bucket ... or whatever ...

anyway, how to measure the doses ? Well ... digital input modules can count within time-frames ... timeframes of a tenth of a second would be about 15ml per 'frame, which (assuming that's also a measure of the accuracy of delivery) might be OK ... depends, obviously, on how fast commands can be processed by Cortex & how fast the signals get-around on Idranet ... etc. I'm assuming, I think, the short timeframes would not be the norm - ie: they would be activated only given appropriate presence !

Bottom-line, I guess, is that I'm thinking maybe software approach (user-macro, even) could be an OK approach here - but would it ?? !!

[toscal]

Don't know if this is possible with the Idratek system.
"using quad-button module, might have one button for hand-wash, another for a cup, another for a bucket ... or whatever ... " But why not just have one button, to control the tap. One press gives you a cup, second press a bucket, third press for bath fill then 2 quick presses turns it off. Or have it similar to a dimming control. ie the longer you hold the button down the quicker the flow rate. Then once its at the correct flow you release the button and to stop press it again. You would possibly need some form of look up table, to do it that way.

[chris_j_hunter]

yes ... thought of that, and maybe, though ...

Idratek isn't so good at dealing with timed inputs - when I wanted it to distinguish between short & long presses, it seemed it couldn't help ... maybe that's out of date ... but I think it;s OK with multiple presses - wonder if there's an issue with how quick ?

another use we had for the four-button module, was as a kitchen timer ... one button for China-tea, another for Ceylon', another for ... etc ... and maybe one button for one minute, another for five, another for fifteen, etc, pressing then in combination according to how long;s required ... and with different tones, over the MFP, in response to each setting, which would be used again when the alarm sounded ... or something like that ... all via a user-macro ...

[Karam]

Firstly I'd say that the way it would probably be done is at the Reflex level by which I mean a feature probably added to existing firmware on a suitable I/O module which would generate a Reflex event (which may directly drive an onboard output eg. relay) after a user defined number of pulses (perhaps internally linearised using rate estimation). So either Cortex or other modules could just directly request a certain volume to be delivered.

I think its unlikely that the same tap would be used for filling cups as well as baths but perhaps cup, kettle, sink full might be a possible scenario for a kitchen sink tap. Anyhow the point I understand is that different volumes may be required from one outlet. I suppose combinations of short/long/multiple presses could be a way to do it or alternatively there is the existing menuing mechanism (ie. button combinations). Presently only the SLD module has short/long button press features - for one reason or another we have not been too keen on this methodology where other options exist, but its possible to add elsewhere in time.

I'm not too sure about controlling flow rate with these on/off valves. I don't know what the dynamics would be like in practice - probably just get a pulsing effect and the water hammering may not be too good for the plumbing.

Karam
IDRATEK LTD

[chris_j_hunter]

sounds good !

>flow-rate ...

for us, anyway, flow-rate adjustment would not be required ... one of the problems with ordinary taps is that they can be & need to be adjusted for flow-rate ... using them would be much quicker if they didn't ! Ditto temperature ... ... whenever they're turned-on, the water is always too hot or too cold, too fast & splashing or too slow, and up/down lever taps are an especial pain ! Our approach has been to have separate basins for hand-washing (eg: in the kitchen & utility room), so that probably helps in our case - ie: one rate & temperature would be fine, and if we wanted something else, we'd have two taps !

with solenoid valves, water-hammer might be a problem, but SFAIK they're used on washing machines & diswashers without that being a problem ... so hopefully would be OK ... could always add something (a small accumulator, or whatever they're called in the plumbing world) to the the plumbing to cure it, if it did occur ...

[chris_j_hunter]

in a month or two, as soon as I've finished plastering & plastering, we'll be wanting to move on this ... it's been a while since the last post, so I thought I would prod the forum, in case anyone had moved on, maybe even tried some valves ?

[chris_j_hunter]

picking up on Paul's request [in the Sub-Meter Electricity Monitoring thread] for some way of having water flow measurement, too ... how about :

http://www.hydralectric.com/category/7-Water+Controls/

which includes :

http://www.hydralectric.com/product/Water+Controls/978-Flow+Meter

as well as the metered valve that came up before, earlier in the thread:

http://www.hydralectric.com/product/Water+Controls/979-Valve+With+Flow+Meter

both of which, I would imagine, would work with the Idratek pulse-counting capable modules ...

plus some water level detection devices :

http://www.hydralectric.com/product/Water+Controls/980-Single+Level+Pressure+Switch

http://www.hydralectric.com/product/Water+Controls/981-Multi+Level+Pressure+Switch

in addition, at :

http://www.hydralectric.com/category/5-Solenoid+Valves/

there are some straight valves - 1,2,3, & 4 port - that might be handy, too


not sure of prices, haven't approached them yet ... when I looked at household appliance spare parts websites, there was a wide range for this sort of thing, mostly not encouraging (!) ... but I also found this - more limited range, but look OK & prices seem better :

http://www.floparts.co.uk/plastic_inlet.htm

they also do an interesting float switch, which could be handy :

http://www.floparts.co.uk/level_switches_miniature.htm

HTH someone ... we're busy researching & designing our plumbing & heating system at the moment, so these things are coming to light !

[chris_j_hunter]

Some more water meters with pulse output :

http://www.smartpowershop.co.uk/department/cold_water_meters/

And a gas meter with pulse output :

http://www.smartpowershop.co.uk/department/diaphram_gas_meters/

NB: see also the Sub-Meter Electricity Monitoring thread for electric meters with pulsed output ...


of course, whether any of these meters are worth the expense rather depends on the savings they can engender !

[Paul_B]

Chris,

Nice find I'll have to have a more detailed look at the datasheets.

I was looking around SmartPowerShop last week but by first impression was that they were significantly more expensive than other suppliers (please see follow-up post for qualification, http://www.wordpress-1219309-4387497...&postcount=30). Although this may have just been first impressions and not like for like comparison

Paul

[SPS]

Smartpowershop

Hi,

I was browsing this and thought i would just add a quick post. I work for smartpowershop and just wanted to say that we try and keep our prices competative.
However if we are way off the mark with some prices then please let me know what they are and we will take another look at them, our aim is to provide a good platform for users to buy products and therefore if our products are too highly priced then we will happily review them.

We can also be pretty flexible with pricing and try to do discounts for quantity as well as for personalised quotes.

Thanks for taking the time to read this. Also any feedback you might have on Smartpowershop would be very welcome since we are look at redesigning the site to make it more user friendly

Thanks,

Oliver
Smartpowershop

[Paul_B]

Oliver,

Okay I should qualify my previous perception. I was looking for a 1-DIN power meter.

On SmartPowerShop you offer a "Memo 3 Direct Connect KWh Meter" at £50.23 incs VAT

On MeterManager they offer a ADM1TE at £28.75 incs VAT

What I need to point out this is not a direct comparison because they are different products. The Memo 3 is rated at 36A and 10Wh pulse whilst the ADM1TE is rated at 30A and 0.5Wh pulse.

Paul