IRROMETER RSU-V User manual

Model RSU-V
INSTALLATION AND OPERATING INSTRUCTIONS
®
RSU-V – Remote Sensing Tensiometer
The IRROMETER RSU-V incorporates a pressure transducer in a potted
waterproof housing. The RSU-V can be installed in the gauge port of any
IRROMETER, thus converting the reading to a voltage signal. Excitation voltage
required is 5 VDC.
Note 1: Consult the factory if modifying an existing MLT.
Note 2: Three wire insulated cable (suitable for direct burial) should be used to connect
Note 2: RSU-V to Electronic Reading Device – #18 AWG size (standard preferred).
Calibration Information
INPUT:5 Volts
VOLTAGE RANGE:0.5 - 4.5 Volts
SPAN:4 Volt Span
TENSION RANGE:0 - 94 kPa
CALIBRATION:.0426 V/cb
2
— WARNING —
Do Not use water containing chlorine or sulfur (distilled preferred)
or cleaners containing chlorine or sulfur with the RSU-V.
When de-airing the transducer equipped IRROMETER (Model RSU-V)
care must be taken to release the vacuum slowly. A sudden release
of the vacuum could cause damage to the pressure transducer,
rendering the instrument inoperable. Transducers damaged by
sudden release of the vacuum are unrepairable and would require
complete replacement of the entire transducer assembly.

3
Reading the RSU-V with a Digital Meter
VACUUM
0kPa
50 kPa
94 kPa
RSU-V (Standard Instruments)
The DVM shows 0.5 V
The DVM shows 2.63 V
The DVM shows 4.5 V
(10/16) #729
LITHO U.S.A.
Optimizing Irrigation . . .
Maximizing Conservation . . .
Worldwide Since 1951
WARRANTY: The IRROMETER COMPANY warrants its products against defective
workmanship or materials under normal use for one year from date of purchase. Defective parts
will be replaced at no charge for either labor or parts if returned to the manufacturer during the
warranty period. The seller’s or manufacturer’s only obligation shall be to replace the defective
part and neither seller nor manufacturer shall be liable for any injury, loss or damage, direct or
consequential, arising out of the use of or inability to use the product. This warranty does not
protect against abuse, shipping damage, neglect, tampering or vandalism, freezing or other
damage whether intentionally or inadvertently caused by the user.
®
1425 Palmyrita Ave., Riverside, CA 92507
951-682-9505 • FAX [phone]
[e-mail]
www.IRROMETER.com
Remote Sensing Units – RSU-V
Multi-conductor wire can be used and twisted pairs are recommended. All
splices should be made with direct burial type waterproof splices, Spears
DBY®or similar. The following table presents recommended maximum
limits for cable extensions to RSU-V transducers. Following these
guidelines should ensure that the voltage loss created by the wire length
will not exceed 1 Centibar (kPa) of the calibrated value.
DISTANCE WIRE SIZE
Up to 200 ft. (61 m) .. . . . . . . AWG UF 18 (1.02 mm, 0.82 sq mm)
Up to 300 ft. (91 m) .. . . . . . . AWG UF 16 (1.29 mm, 1.31 sq mm)
Up to 400 ft. (121 m) .. . . . . . AWG UF 14 (1.63 mm, 2.08 sq mm)