Zero Point Adjustment - YOKOGAWA DPharp EJXC80A User Manual

5.2

Zero Point Adjustment

After completing preparations for operating the
transmitter, adjust the zero point.
Zero point adjustment can be done by turning the
transmitter's zero-adjustment screw or by using
the communicator. This section describes the
procedure for the zero-adjustment screw. For the
communicator procedure, see the communication
manual.
IMPORTANT
Do not turn off the power to the transmitter
immediately after performing a zero point
adjustment. Powering off within 30 seconds of
performing this procedure will return the zero
point to its previous setting.
NOTE
Before performing this adjustment, make sure
that the external zero adjustment function has
NOT been disabled by a parameter setting.
To check the output signal, use a digital multimeter,
calibrator, or communicator.
<5. Operation>
(1) When you can obtain Low Range Value
from actual measured value of 0% (0 kPa,
atmospheric pressure);
The zero-adjustment screw is located inside the
cover.
Use a slotted screwdriver to turn the zero-
adjustment screw. Turn the screw clockwise
to increase the output or counterclockwise to
decrease the output. The zero point adjustment can
be made with a resolution of 0.01% of the setting
range. The degree of zero adjustments varies with
the screw turning speed; turn the screw slowly to
make a fine adjustment, quickly to make a rough
adjustment.
When adjusting the transmitter zero point, the
liquid level in a tank does not have to be set to
the low limit (0%) of the measuring range; use a
digital manometer or a glass gauge to match the
transmitter output signal with the actual measured
value.
(2) When you cannot obtain Low Range Value
from actual measured value of 0%;
Adjust the transmitter output to the actual measured
value obtained by a digital manometer or a glass
gauge.
[Example]
The measuring range of 50 to 250 kPa; the actual
measured value of 130 kPa.
Actual measured value=
Turn the screw to match the output signal to the
actual measured value.
5-3
Zero-adjustment
screw cover
F0507.ai
130–50
x100=40.0%
250–50
(=10.4mA)
IM 01C25W01-01EN