Yokogawa EJX210B - Manual (Page 30)

<7. Operation>
7-2
IM 01C27C01-01EN
• Measurement range (measurement lower/
upper limit, unit).
7.2 Zero Point Adjustment
After completing preparations for operating the
transmitter, adjust the zero point. There are two
zero point adjusting ways.
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.
(1) When you can obtain Low Range Value
from actual measured value of 0% (0 kPa,
atmospheric pressure);
F0703.ai
Zero-adjustment
screw cover
Figure 7.3 External Zero Adjustment Screw
■ Using the Zero-adjustment screw
Before adjusting zero point, make sure followings.
• The External zero trim parameter
(External Zero Trim) is “Trim on”. For details,
refer to section 8 “Setting Parameters”.
• 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.
■ Using the Device Configuration Tool
Refer to subsection 8.3.11 “Zero Point Adjustment
and Span Adjustment”.
(2) When you cannot obtain Low Range Value
from actual measured value of 0%;
When adjusting the transmitter zero point, the liquid
level in a tank can not 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.
Adjust the transmitter output to the actual measured
value obtained by a digital manometer or a glass
gauge.
[Example]
The measuring range of 0m to 2m; the actual
measured value of 0.8m.
0.8
2
Actual measured value= x100=40.0%
■ Using the Zero-adjustment screw
Turn the zero adjustment screw to match the output
signal to the actual measured value.
■ Using the Device Configuration Tool
Refer to subsection 8.3.11 “Zero Point Adjustment
and Span Adjustment”.