2 zero point adjustment, 1 adjusting zero point for differential pressure, Zero point adjustment -2 8.2.1 – Yokogawa EJX930A User Manual
Page 49: Adjusting zero point for differential pressure -2, Important

<8. Operation>
8-2
IM 01C25R01-01E
■ Confirming that Transmitter is Operating
Properly
Using the HART communicator
• If the wiring system is faulty, ‘No device found at
adress O Poll' or communication error’ appears
on the display.
• If the transmitter is faulty, ‘error message’
appears on the display.
Using the integral indicator
• If the wiring system is faulty, the display stays
blank.
• If the transmitter is faulty, an error code is
displayed.
Self-diagnostic error on the integral indicator
(Faulty transmitter)
F0802.ai
Figure 8.2
Integral Indicator with Error Code
NOTE
If any of the above errors are indicated on
the display of the integral indicator or the
communicator, refer to subsection 9.5.2 for the
corrective action.
■ Verify and Change Transmitter Parameter
Setting and Values
The parameters related to the following items are
set at factory as specified in order.
• Calibration range
• Software damping (optional)
Other parameters like following are shipped with the
default setting.
• Low-cut
• Process alarm setting
• Write protection
To confirm or change the values, see
IM 01C25R02-01E or 01C25R03-01E.
8.2 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
been enabled by a parameter setting.
External zero adjustment function only to the
differencial pressure signal.
To check the output signal, use a digital multimeter,
calibrator, or communicator.
8.2.1 Adjusting Zero Point for Differential
Pressure
Before adjusting zero point, make sure that the
equalizing valve is open.
F0803.ai
Zero-adjustment
screw cover
Figure 8.3
External Zero Adjustment Screw