Yokogawa EJA115 - Manual (Page 5)

IM 01C22T01-01E 1-2
1. ZERO POINT ADJUSTMENT
1.1.1 Using the HART Communicator
(1) Zeroing — Zero trim
NOTE
Zero trim carries out the zero adjustment and
sets the input values at present, equal to 0
mmH
2
O. Use this setting to set LRV = 0 mmH
2
O.
1
1. Device setup
2. Diag/Service
3. Calibration
3. Sensor trim
1. Zero trim
EJA:
WARN-LOOP should be
removed from
automatic control
ABORT OK
F0102.EPS
Press OK (F4).
(OK)
2
EJA:
WARN-This will affect
sensor calibration
ABORT OK
Press OK (F4).
(OK)
3
EJA:
Apply O input to
sensor
ABORT OK
A pressure of 0 mmH
2
O is applied.
Press OK (F4) after the pressure
has become stable.
(OK)
(2) Arbitrary Level Adjustment — Lower
Sensor Trim
This zero adjustment applies to tank level measure-
ments, etc. where the actual tank level cannot be set to
zero. For this adjustment, use the actual tank level
obtained with a glass gauge or the like to meet the
DPharp output.
2500 mmH
2
O
0 mmH
2
O
Actual level
1350 mmH
2
O
DPharp span: 0 to 2500 mmH
2
O
Actual level: 1350 mmH
2
O
Transmitter output: 1383 mmH
2
O
DPharp
F0103.EPS
1
1. Device setup
2. Diag/Service
3. Calibration
3. Sensor trim
2. Lower Sensor Trim
EJA:
Apply low pressure
ABORT OK
F0104.EPS
Check the tank level at present, and
press OK (F4).
(OK)
2
EJA:
Press OK when
pressure is stable
ABORT OK
Press OK (F4).
(OK)
3
EJA:
ENTER applied
Pressure Value
0.000 mmH2O
0.000
HELP DEL ABORT ENTER
Enter the value of the actual level
(1350 mmH
2
O), and press ENTER
(F4).
(ENTER)
‘1 3 5 0’
NOTE
Lower Sensor trim adjusts the input value at
present. See Fine Input Adjustment for detail.
1.1.2 Using the Transmitter Zero-adjust-
ment Screw
Turn the zero-adjustment screw on the outside of the
transmitter case using a slotted screwdriver. Turn the
screw to the right to increase the zero point or to the
left to decrease the zero output; the zero adjusts in
increments of 0.01% of the range setting.
Note that the amount of adjustment to the zero point
changes according to the speed at which the screw is
turned. To make fine adjustments, turn the screw
slowly; to make coarse adjustments, turn the screw
quickly.
Note: When a zero point adjustment has been made do not turn of
the transmitter less than 30 seconds after adjustment.