Installation
Step 1:
You can install one or two GP1-PBA1s in the GP1. Align the GP1-PBA1 with the
CH1
or
CH2
terminals so that one of its 5 pins overhangs the GP1 terminal block. Insert the
remaining
four
pins into the
four
screw terminals of
CH1
or
CH2.
Tighten the screws.
Pin not
connected
CH2 (PWR)
Pin not
connected
CH1 (PWR)
SWT tensiometers
Sensor connection
Connect tensiometer wires to
GP1-PBA1 terminals:
Brown Vref
White CH(-)
Black CH(+)
Blue GND
Connect the screen (thick black)
to any GND terminal on the GP1
board.
This connection method gives
negative hPa readings for
negative potentials (i.e. suction).
SWT tensiometer connection to CH2
Step 2: Measure the zero offset
Before programming the GP1 for tensiometer readings you need to measure the
zero offset
of the GP1-PBA1.
SWT3
and
SWT4 tensiometers:
remove the transducer or carefully unscrew the
ceramic cup from the tensiometer. Remove any water droplets from the access hole to
the pressure transducer by gently tapping the unit. Connect the tensiometer to the
GP1-PBA1.
Refer to the tensiometer User Manual and carefully reassemble and refill the
tensiometer after measuring the zero offset.
©
2006 Delta-T Devices Ltd
Page 2
