Yokogawa EJA440E - Manual (Page 23)

<3. Operation>
3-15
IM 01C25T03-01E
FEED NO OK
SET
J11:P ZERO ADJ
0.00000 kPa
CLR DEL ESC
SET
J11:P ZERO ADJ
0.00000 kPa
+ 0
A pressure of 0 kPa is applied.
Press the key twice
after the pressure has become
stable.
Zero adjustment is completed.
Press the (OK) key.
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Transmitter measures pressure of
0.03585 kPa.
Transmitter measures pressure of
0.00000 kPa.
A11:PRES
0.03585 kPa
A11:PRES
0.00000 kPa
a-2. Level Adjustment
The zero adjustment by the parameter J11: P ZERO
ADJ calibrates the transmitter output corresponding
to the actual tank level. To perform this adjustment,
first use a glass gauge or the like to determine the
actual tank level, then enter the correct data as
shown below.
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25.00 kPa
0.00 kPa
Actual level
13.50 kPa
DPharp span: 0 to 25.00 kPa
Actual level: 13.50 kPa
Transmitter output: 13.83 kPa
DPharp
CLR DEL ESC
SET
J11:P ZERO ADJ
0.00000 kPa
+ 045.0
+ 13.5
Enter the present actual level,
13.5 kPa.
Press the key twice.
The measured pressure is
changed to 13.5 kPa.
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Transmitter measures present
pressure of 13.83 kPa.
A11:PRES
13.83 kPa
A11:PRES
13.5000 kPa
a-3. Using External Zero-adjustment Screw
This method permits zero adjustment without the
BT200. Use a slotted screwdriver to turn the zero-
adjustment screw. See the hardware manual for
details.
Note that the parameter J55: EXT ZERO ADJ must
be ENABLE to perform this adjustment.
Follow the procedure below to enable or inhibit zero
point adjustment from the zero-adjustment screw
on the transmitter.
This is set to ENABLE when the instrument is
shipped.
• Example: Inhibiting zero adjustment by the
external zero-adjustment screw.
ESC
SET
J55:EXT ZERO ADJ
ENABLE
< ENABLE >
< INHIBIT>
Use the or key
to select
INHIBIT.
Press the key twice to
enter the setting.
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Then press the (OK) key.
b. Full Sensor Trim (J11: P ZERO ADJ, J12: P
SPAN ADJ, J15: P ZERO DEV, J16: P SPAN
DEV)
Full sensor trim is carried out with a series of the
procedure of J11: P ZERO ADJ and J12: P SPAN
ADJ. Also, you can manually perform the trimming
procedure by using J15: P ZERO DEV and J16: P
SPAN DEV.
The full sensor trim is a two-point adjustment,
and the lower point adjustment should always be
performed before the upper point adjustment in
order to maintain the pitch between the zero and
100% points within the calibration range.
In the manual method, the reference pressure
should also be applied to the transmitter at both
lower and upper point of trim ends. Without the
reference pressure, J15: P ZERO DEV and J16: P
SPAN DEV may not represent the correct value of
adjustment point for each.