IRROMETER RSU-C Installation And Operating Instructions

INSTALLATION AND OPERATING INSTRUCTIONS
Model RSU-C
— CAUTION —
Do Not Install by Hand
You must use a wrench on the brass fitting
(9/16" wrench for the 1/4" transducer or 1/2" wrench for the 1/8" transducer)
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RSU-C – Remote Sensing Tensiometer
transducer and electronics in a potted waterproof
housing. The RSU-C can be installed in the gauge
port of any IRROMETER, thus converting the reading
to a 4-20 ma loop current signal. It can be interfaced
with a 4-20 ma loop current terminal or to an A/D card
designed to read voltage. Excitation current required
is 12 – 24 VDC.
The RSU-C is available in two different calibrations:
Standard Instruments (RSU-C-93)
4-20mA = 0-93 kPa (0.172 mA per kPa)
Low Tension Instruments (RSU-C-34)
4-20mA = 0-34 kPa (0.471 mA per kPa)
Note 1: Connection size must be specified when ordering RSU-C only: 1/4'' MNPT or 1/8'' MNPT.
Note 2: Two wire insulated cable (suitable for direct burial) should be used to connect RSU-C to
Electronic Reading Device – #18 AWG size (standard preferred).
For devices that cannot read a current loop but can read a voltage, a resistor can be used to
translate the current loop into a voltage. A 250 ohm resistor will convert the 4-20mA output into a
1V to 5V reading. The following figure illustrates this configuration:
Figure 1
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The IRROMETER RSU-C incorporates a pressure
Do Not use water containing chlorine or sulfur (distilled preferred)
or cleaners containing chlorine or sulfur with the RSU-C.
When de-airing the transducer equipped IRROMETER (Model RSU-C)
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.
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— WARNING —
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