SCADA and soil moisture sensors

[Peter Johansson <p.johansson@streats.co.nz>]

Dear Mr Grogan

1)  The input voltage for Aquaflex soil moisture sensors are as follows:

a) 4-20mA output version of sensor

Voltage:  9 - 26 V DC (mains or low voltage AC available as an option)

b) Frequency/pulse output version of sensor, suitable for driving a 5 volt
logic input

Voltage:  11 - 14 VDC

c) Frequency/pulse output version of sensor - contact closure, suitable for
driving a clean contact input

Voltage:  18 - 26 VAC or 18 - 26 VDC


2)  Yes, the electrical interfaces are protected from spikes and surges.


Best regards, Peter Johansson

-----Original Message-----

Sent: Friday, 12 March 1999 06:58   Subject: Re: SCADA and soil moisture
sensors

>Marty Grogan writes

What is the input voltage range? Are the electrical interfaces protected
>from spikes and surges?<

>Peter Johansson wrote

"Aquaflex Soil Moisture Sensors will interface with most S.C.A.D.A systems.
Aquaflex has been designed to overcome the traditional problems associated
with measuring the soil moisture content at one point only, and in a
relatively small volume of soil. Aquaflex measures average soil moisture
over a 3 meter length and in a cylindrical volume of 6 litres of soil.  The
following are common outputs available, all suitable for connecting to a
wide range of irrigation controllers, weather stations, data loggers,
industrial controllers etc:

a) 4-20mA output

b) Frequency/pulse output, suitable for driving a 5 volt logic input

c) Frequency/pulse output - contact closure, suitable for driving a clean
contact input

Custom outputs are available on request.<


_________________________________________________________________
Peter Johansson

Streat Instruments Limited
PO Box 8269, Christchurch
New Zealand
Tel               + 64 - 3 - 348 6443, extn 718
Fax              + 64 - 3 - 348 6256
E-Mail          p.johansson@streats.co.nz
Web-site      www.streats.co.nz

    a.. Moisture Measurement & Control Instrumentation
    b.. Industrial Process Automation
See the Aquaflex Soil Moisture Sensor, Agricultural Field Days, Lincoln,
24-26 March

We are expanding - additional Distributors are welcome