SWT5 tensiometer:
fit the supplied Calibration
Resistors (10k
Ω
±1%) and wire link as shown.
Remove these and connect the tensiometer after
measuring the zero offset
.
Refer to the GP1 Quick Start Guide and:
1. Cold reset the GP1: press the
Reset
button, hold down for 5 or 6 seconds.
Release the button when you see a
second sequence of LED flashes.
2. Connect the GP1 to your PC, start
DeltaLINK, select the
Sensors
window and click
Read
now
.
3. Make a note of the voltage reading on
the channel which is connected to the
GP1-PBA1. This is the
zero offset
value which you will need when
programming the GP1, and should be in the region of 1250mV ± 50mV.
Step 3: Program the GP1 for tensiometer readings
1. Connect the GP1 to your PC and start DeltaLINK.
2. Select the
Program
window and click
Change
.
3. Double-click the channel with GP1-PBA1 installed.
4. In
Voltage Channel Properties:
•
Enter a
Label
•
Select
Sensor Type
: <custom>.
•
Enable
Warmup
, and enter 1s.
•
For
Units
enter ‘hPa’
•
Select no
Linearization Table
•
Calculate and enter
a0
=
–
0.7067 x
zero offset
•
For
a1
enter 0.7067
•
For
Minimum
,
Maximum
and
Resolution
enter -855, 1005 and 0.1
hPa.
•
Click
OK
when finished.
5. Clear or re-program other GP1
channels and select other program
options as required.
6. Click
Apply
when finished, to install the modified program in the GP1.
7. Select the
Sensors
window and click
Read now
to check sensor operation.
8. Select the
Logger
window and click
Start
to start logging.
©
2006 Delta-T Devices Ltd
Page 3
