results of LVDT inquiries

VWSHEP at volcani.agri.gov.il VWSHEP at volcani.agri.gov.il
Fri Dec 29 21:19:18 EST 1995

Summary of LVDT Info from email and other inquiries:


1. Lucas Schaevitz
N. America:
Lucas Control Systems Products
Schaevitz Sensors
1000 Lucas Way
Hampton, Va. 23666
Fax: 800-745-8004

Lucas Control Systems Products
Schaevitz Sensors
543 Ipswich Road
Slough, Berks SL1 4EG
0753-537 622
Fax: 0753-823 563

Types: AC and DC

2. Solartron Metrology (markets or manufactures Schlumberger Industries
Steyning Way, Southern Cross Industrial Estate
Bognor Regis, West Sussex
PO22 9ST
+44 0 1243 825011
Fax: +44 0 1243 861244

Also Locations in France, Germany and USA

U.S.A.: Tel 716 634 4452    Fax: 716 634 1225
France : 33 1 69 53 63 63   Fax: 33 1 60 13 37 06
Germany: 0208/31026         Fax: 0208/31441

Types: AC and DC

3. SensoTec, U.S.A.
Address Unknown
Phone: 1-800-848-6564
Fax  001-614-486-0506
Types: AC and DC

4. Macro Sensors (Division of H.A. Schaevitz Technologies !?!)
600 Main St.
Riverton, N.J. 08077-1419

001 609 662 8000
Fax: 001 609 786 1939

Types: AC or DC

5. Omega
Leicester, U.K.
Phone 0455 285520
Fax 0455 283 912

0438 365671
Fax: 0438 356 203

6. Hottinger Baldwin Messtechnik GMBH
100 151, D-64201 Darmstadt
Im Tiefen See 45, D-64293 Darmstadt
Tel: 06151 803-0
Fax: 06151 894896

Types: AC

7. Micro-epsilon Messtechnik, Germany
+49 8542 168 0
Fax: +49 8542 16890

Types: AC only

Other Info:
There are alot of manufacturers around, but if you are looking for
a 12 V DC system there aren't too many options, and they're all about
the same price (approx $300/unit). In the end we ordered from Solartron.

A 10 Channel LVDT growth recording system is available from:
Mosaic Systems
P.O.Box 914,
Palmerston North
P.O.Box 8238
Auckland, N.Z.

Phone: 06 355 4196, 09 377 7963
Fax: 06 355 4197,   09 307 6763

I found out about two strain-guage systems that do the same thing
for a fraction of the price. One is described below in the digest
from Dynamax. A second is a ready to use dendrometer produced by 
an Israeli strain guage company, but is not ready for marketing.


Several people answered that they use Hewlett Packard LVDT's. From
my inquiries it seems that HP stopped manufacturing LVDT's and passed
along the manufacturing to Lucas Schaevitz.

Compiled and Edited by:
Shabtai Cohen, Ph.D.
EMAIL: vwshep at volcani.agri.gov.il
FAX: 972-3-9604017
PHONE: 972-3-9683698

Dept. of Environmental Physics and Irrigation
Institute of Soils and Water
A.R.O. Volcani Center
P.O.B. 6
Bet Dagan 50250

Edited messages in digest form:
From:   WINS%"p.vangardingen at ed.ac.uk"  1-NOV-1995 16:33:35.06
From: Paul van Gardingen <PAULVG at srv0.bio.ed.ac.uk>
Organization:  Edinburgh University

We have used quite a variety over the years but now tend to go for 
the simple models that have DC input and output.

The ones we have used are manufactured by sangamo/schumberger.  One 
thing to check is that the ones that you choose are weatherproof.

Dr Paul van Gardingen             Institute of Ecology
                                  & Resource Management
E-mail: P.vangardingen at ed.ac.uk   The University of Edinburgh
Phone:  +44 (0)131 535 4066       School of Agriculture
                                  West Mains Road
Fax :   +44 (0)131 667-2601       Edinburgh EH9 3JG, Scotland

From: mryan at lamar.colostate.edu (Mike Ryan)
Rocky Mountain Experiment Station 
240 West Prospect RD
Ft Collins, CO 80526-2098
(970) 498-1012 phone
(970) 498-1010 fax

ADC in England has "electric dendrometers" for measuring stem and fruit 
expansion.  Their address is adc.co.uk 

Pindar Road 
Hoddeston, Herts.
EN11 0AQ
fax: +44 1992 444567

From:   WINS%"<S.J.M.Caporn at mmu.ac.uk>"  1-NOV-1995 18:49:42.83
From: "S.CAPONE" <S.J.M.Caporn at mmu.ac.uk>

I have a research project with Dr Keith Parkinson of PPSystems (UK) to 
develop a new instrument for measurement of extension of leaves. It 
will be cheaper than LVDT's. My student Sam Jackson is working on 
this; I will get her to send any marketing information as it becomes 
available. Yours sincerely,

Dr Simon J.M. Caporn
Senior Lecturer in Environmental Biology
Division of Environmental Science
The Manchester Metropolitan University
Crewe and Alsager Faculty
Crewe Green Road
Cheshire CW1 1DU

From:   WINS%"George.Koch at nau.edu"  1-NOV-1995 19:17:59.08
From: George.Koch at nau.edu (George Koch)

try Agricultural Electronics Corporation, P.O.Box 50291, Tuscon AZ 85703-1291
tel & fax:602 624 7656.  William Gensler is the person to contact there. 
I haven't used their products, but the specs. look good. 

Dr. George W. Koch
Assistant Professor
Department of Biological Sciences
Northern Arizona University
Flagstaff, AZ 86011-5640
Tel: 520 523 7150
FAX: 520 523 7500

From:   WINS%"<aphalo at cc.joensuu.fi>"  2-NOV-1995 09:00:24.82
From: "Pedro J. Aphalo" <aphalo at cc.joensuu.fi>
Organization: University of Joensuu

Some distributors which carry HP's LVDTs and/or "own brand" types are:

RS Components International.
Fax: +44 1536 204237 
Fax them to find your local distributor and get 
their free catalogue (LVDTs are in pages 854-856).
Get also their data sheet No. 9681.

Farnell Components used to sell HP's LDVTs but they are not in their 
latest catalogue... 

 Pedro J. Aphalo
 University of Joensuu, Faculty of Forestry
 P.O. Box 111, FIN-80101 Joensuu, FINLAND
 e-mail: aphalo at cc.joensuu.fi
 fax: +358 73 151 4444 (or +358 73 151 3590)
 tel: +358 73 151 4406                         ,,,^..^,,,

          Thu,  2 Nov 95 10:51:05 EST
From: "Glyn Bengough" <CEPGB at scri.sari.ac.uk>

Lucas Schaevitz (in North America - 7905 N. Route 130 Pennsauken, NJ 
08110, Fax 609/662-6281) supplies LVDTs and has European and North 
American outlets.

Glyn Bengough
Department of Cellular and Environmental Physiology,
Scottish Crop Research Institute,
Dundee DD2 5DA, Scotland

Telephone: National 01382 562731 extension 2527
Fax: National 01382 562426  International +44 1382 562426

From:   WINS%"<morisj at essex.ac.uk>"  2-NOV-1995 21:00:10.08
From: Dr James I L Morison <morisj at essex.ac.uk>

IN the UK they are readily available through all general electronics
distributors, such as RadioSpares (RS). A quick look in the catalogue shows
a variety of high precision ones, around 100 pounds stlg; don't know what
source. I can enquire if you like. Schlumberger used to make them, I know.

Dr. James I.L. Morison,
Department of Biological and Chemical Sciences,
The John Tabor Laboratories,
University of Essex,
Wivenhoe Park, 
Colchester CO4 3SQ
Essex     UK
tel : +44 (0)1206 873327
fax: +44 (0)1206 873416
email : morisj at essex.ac.uk
          Sun,  5 Nov 95 22:49:38 EST
From: "Trought, Michael" <TROUGHTM at whio.lincoln.ac.nz>
Organization: Lincoln University

I have just pruchased a 10 channel LVDT system from Mosaic Systems, 
Palmerston North, based on a design prepared by Dr Sandy Lang, 
HortResearch, Palmerston North.  I am very pleased with the system.

I suggest that you contact Sandy:  Slang at hort.cri.nz

Dr Mike Trought                Telephone    (64) (03) 325 2811
Department of Plant Sciences   Fax          (64) (03) 325 3843
PO Box 84                      Internet     Troughtm at Lincoln.ac.nz
Lincoln University
New Zealand
          Tue,  7 Nov 95 11:05:31 EST
From: sja <S.Allen at unixa.nerc-wallingford.ac.uk>

I heard recently of a company in the USA who have started to
manufacture two systems (based on strain gauges) specifically designed
for accurately measuring the expansion of stems and fruits. The company
(Dynamax) is the same one which manufactures stem heat balance gauges
for measuring sap flow rates in plant stems.

Dynamac Inc.
9888 Bissonnet
Suite 150
Texas 77036

Tel: +1 713-771-4224
Fax: +1 713-771-4102

The model codes for their 'electronic dendrometers' are DEX-70 and

Simon Allen
Institute of Hydrology, UK

          Wed,  8 Nov 95 00:36:08 EST
From: "Sandy Lang" <slang at hort.cri.nz>
Organization:  Hort Research, Palmerston North, NZ

Mail:  HortResearch
       Private Bag 11 030
       Palmerston North 
       New Zealand
Tel:   +64-6-356-8080
Fax:   +64-6-354-6731
From:   WINS%"<CEPGB at scri.sari.ac.uk>"  9-NOV-1995 12:58:23.04
From: "Glyn Bengough" <CEPGB at scri.sari.ac.uk>
Date:          Thu, 9 Nov 1995 10:55:38 GMT

Thanks for your email - the fax number is as written on the company 
brochure.  You could try the European number FAX +44 1753 823563 (if 
dialing internationally). 
(Lucas Schaevitz, 543 Ipswich Road, Slough, Berkshire, SL1 4EG).

Glyn Bengough
Department of Cellular and Environmental Physiology,
Scottish Crop Research Institute,
Dundee DD2 5DA, Scotland

Telephone: National 01382 562731 extension 2527
Fax: National 01382 562426  International +44 1382 562426

          Mon, 20 Nov 95 12:37:50 EST
From: "Pieter van de Sanden, AB-DLO, Wageningen" <P.A.C.M.VANDESANDEN at ab.dlo.nl

I have been working with LVDT's measuring the 
volume growth of individual tomato fruits (in response to root environment 
water potential in aerohydroponics).
My LVDT's are from Schlumberger Transducers, Steyning Way, Southern 
Cross Industrial Estate, Bognor Regis, Wets Sussex, PO22 9ST, UK. Phone 
(0243)825011, Fax 861244 (address data dated 1990 !).
I used the ST200 type in combination with the CAH16 - 16 channel LVDT 
conditioning PCB. If you are interested I can fax you some of the info-
leaflets I have on these equipment.
My personal experience: these sensors are very sensitive and as such can 
give you information on a short time scale, but they are also very 
temperature-sensitive. And the temperature-sensitivity is very hard to 
calibrate, primarily since it is very hard to establish what temperature the 
sensor is sensing. So, it is important to weight the advantage of sensitivity to 
displacement against the sensitivity to temperature. Maybe next time I 
would chose a less temperature-sensitive type and consequently a sensor 
less sensitive to displacement. It is up to you to calculate from the research 
question you want to answer what displacement resolution you need and 
look for a sensor which has a temperature-sensitivity that does not override 
the resolution/range you want to study. I have been working in a fytotron and 
still there the climate control, especially dark/light transition, causes effects 
which I am hardly able to describe to temperature or to fruit 

Pieter van de Sanden
Research Institute for Agrobiology and Soil Fertility
PO Box 14
NL - 6700 AA  Wageningen,  the Netherlands

Peter Minchin, HortResearch,  
Private bag 31-313, Lower Hutt, New Zealand.
ph: +64-4-5690-232  Fax: +64-4-5690-372  e-mail: PMinchin at hort.cri.nz

Dr David Yates                     
Botany Department                   
The University of Queensland     
Brisbane, Qld, 4072
phone +61 7 3365 2070
fax   +61 7 3365 1699


Moshe Cohen Aman
Cabrils (Barcelona) 

Cohen at cabrils.irta.es

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