<7. Operation>
7-3
IM 01C25F01-01E
7.2 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.
NOTE
• Because the output value may be affected
by the transmitter’s mounting position,
zero adjustment should be executed after
installing the transmitter. If you have to adjust
zero point before installation, make the
posture of the transmitter close to the actual
installation state when adjusting zero.
• The factory adjusts the zero point of the
absolute pressure transmitters (EJX510A,
EJX610A, and EJA510E) with making the
transmitter in the standing position before
shipment.
To check the output signal, use a digital multimeter,
calibrator, or communicator.
Zero-adjustment
screw cover
F0704.ai
Figure 7.4
External Zero-adjustment Screw
The zero-adjustment screw is located inside the
cover.
(1) When you can obtain the Low Range Value
from the actual measured value of 0% (0
kPa, atmospheric pressure);
For pressure measurement using gauge pressure
transmitters, follow the steps below before
performing zero point adjustment.
1) Close the tap valve (main valve).
2) Loosen the fill plug so that the pressure applied
to the transmitter is only the head of the seal
liquid.
3) Adjust the zero point at this status.
4) After the adjustment, close the fill plug and then
gradually open the tap valve.
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. Since the degree of the zero adjustment
varies with the screw turning speed, turn the screw
slowly to make a fine adjustment and quickly to
make a rough adjustment.
