Hello, In my case, i use an underwater sensor in my "water room" (little pond at the end of the flumme just before the pipe line) The regulator (Micro PLC SCHNEIDER with homemade program) use the 4-20mA signal to regulate the water level.
It's a BOURDON HAENNI SENSOR for 0 to 1.6 metres of water I paid it (03/2005) 436 Euros Without Tax (IN FRANCE) Very precise 20 cm max between the min and max level Data site : Francis turbine, 11 Metres head, 800 l/s 100KW 100 m etres flumme, 20 m3 "water room" 80 metres of pine line D 800 mm I think the sensor you would use is not precise if you use only a few centimeters on a 10 metres sensor (= 1 bar) And if the sensor is ok, check the "regulator" accuracy, sometimes there is only a few points on a 4-20 mA inputs. If you have 1024 point, 1 point is 1 centimetres on a 10 metres sensor. It ok to regulate in the 1 metres range, not in the 10 cm I think the place you want to put your sensor is not very good, if you have a pipe line feeding your turbine, you have little waterhammer in this part when you shut the vane. So it's very difficult to make a good regulation with this information. (the sensor look a peak of pressure and indicate a speed up water more than the real) Regards Eric ----Message d'origine---- >A: "'[email protected]'" <[email protected]> >Copie à: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> >De: "Martin.Leahy" <[EMAIL PROTECTED]> >Date: Wed, 26 Oct 2005 13:53:41 +0100 >Sujet: [microhydro] Head sensor for hydro > >I have a site with 450 mm (18 inch) Francis turbine housed in a pressurised >concrete water chamber (approx. 2.5 m x2.5 x 2.5m) and GE F650 bay >controller. Head varies between 9 and 6 m and I would like to measure and >use this head in control of the turbine guide vanes. I can easily install a >pressure sensor by drilling and tapping into the access panel of the chamber >about 0.5 m from the nearest guide vane. > >I am concerned about the turbulence (although this may be averaged out). > >Also, the spec I guess should be stainless steel, 4 - 20 mA o/p, 0-1 bar. >There appears to be a large differential in prices (see below from RS). > >Regards, > >Martin > > >****************************************************** > > > Cable stock no. price each > Range Length 1+ > 0 to 5m WG 15 m 395-7101 336,00 > 0 to 10m WG 15 m 395-7117 336,00 > 0 to 20m WG 25 m 395-7123 379,00 > > > > > > > >Water head pressure equals 100mbar per metre which can be effectively >measured using submersible pressure transmitters in atmospheric tanks. >Output is proportional to level. >High accuracy > >Easy installation > >Measures tanks and boreholes > > >technical specification > >Signal Output 4-20mA >Zero/Span Tolerance 0·1% >Supply Voltage 8 to 40Vdc >Operating Temperature -20°C to +85°C >Long Term Drift 0·15% of max span/year >Accuracy 0·15% FS >Max Overpressure 2 x FS >Rating IP68 > > >************************************************* >GP Pressure Transducers/Transmitters: >One piece stainless steel body > >Multipurpose, high performance > >Temperature compensated, strain gauge technology > >0-100mV output (transducers) > >4-20mA output (transmitters) > >0-5V output (transducers) > > >technical specification > >Over working pressure 2 x range (x5 burst pressure) (max) >Accuracy ±0.25% (typ) >Excitation Voltage 10Vd.c. (0-100mV transducers) > 6·5-35Vd.c. (0-5V transducers) > 7·5-35Vd.c. (4-20mA transmitters) >Output (transducers) 0-100mV > 0-5V >Output (transmitters) 4-20mA >Operating range -40 to +125°C (transducers) > -40 to +100°C (transmitters) > >stock no. price each > transducers conn. (0-100mV) 1+ 6+ > 0-1 bar g 1/4 BSP 249-3864 132,50 127,00 > 0-6 bar g 1/4 BSP 249-3959 132,50 127,00 > 0-10 bar g 1/4 BSP 249-3858 132,50 127,00 > 0-25 bar g 1/4 BSP 249-3965 132,50 127,00 > 0-40 bar g 1/4 BSP 249-3836 132,50 127,00 > 0-100 bar g 1/4 BSP 249-3820 132,50 127,00 > 0-250 bar g 1/4 BSP 249-3971 132,50 127,00 > 0-400 bar g 1/4 BSP 348-8217 132,50 127,00 > transmitters conn. (4-20mA) > 0-1 bar g 1/4 BSP 249-3870 162,00 155,00 > 0-6 bar g 1/4 BSP 249-3943 162,00 155,00 > 0-10 bar g 1/4 BSP 249-3937 162,00 155,00 > 0-25 bar g 1/4 BSP 249-3921 162,00 155,00 > > >******************************************************** > > > >********************************************************** > >Kind Regards, > >Martin > > > > > > > >Does your company feature in the microhydro business directory at >http://microhydropower.net/directory ? If not, please register free of charge >and be exposed to the microhydro community world wide! > >NOTE: The advertisements in this email are added by Yahoogroups who provides >us with free email group services. The microhydro-group does not endorse >products or support the advertisements in any way. > >More information on micro hydropower at http://microhydropower.net > >To unsubscribe: send empty message to [EMAIL PROTECTED] >Yahoo! Groups Links > > > > > ------------------------------------------------------------- NetCourrier, votre bureau virtuel sur Internet : Mail, Agenda, Clubs, Toolbar... Web/Wap : www.netcourrier.com Téléphone/Fax : 08 92 69 00 21 (0,34 TTC/min) Minitel: 3615 NETCOURRIER (0,16 TTC/min) ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. 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