Yokogawa EJA530A - Manual (Page 45)

IM 01C21F01-01E 8-14
8. BRAIN TERMINAL BT200 OPERATION
(b)-2 Follow the procedure below to use J11: ZERO
DEV.
ECS
ESC
SET
J11:ZERO DEV.
2.50 %
0 Since “J11: ZERO DEV.” contains
the previous correction, obtain the
correction value by adding –1.0% to
it. 2.50% + (–1.0%) = 1.50%
Set the correction value, 1.50.
Press the key twice.
F0830.EPS
Present output is 41.0%.
Output error = 40.0 – 41.0 = –1.0%.
A10:OUTPUT (%)
41.0 %
The output is changed to 40%.
A10:OUTPUT (%)
40.0 %
SET
J11:ZERO DEV.
2.50 %
1.50
When the zero point is adjusted, the displayed value
of A40 is as follows.
[Example]
When the zero point is shifted by 20 kPa for the
actual pressure, the parameter of A40 indicates 50
kPa.
F0839.EPS
70 kPa
20 kPa
0 kPa
Zero adjustment
volume(J11)
Actual differential
pressure/pressure Input value
of A40
50 kPa
0 kPa
Zero
adjustment
(c) Zero Point Adjustment Using the External Zero
Adjustment Screw
• Enabling/inhibiting of zero point adjustment using
the external zero-adjustment screw on the transmitter
(J20: EXT ZERO ADJ)
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
J20:EXIT ZERO ADJ
ENABLE
< ENABLE >
< INHIBIT> Use the or key to
select “INHIBIT.”
Press the key twice to
enter the setting.
F0831.EPS
• Zero point adjustment using external zero-adjust-
ment screw on the transmitter
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
off the transmitter less than 30 seconds after adjustment.
(13) Span Adjustment
Each DPharp EJA series transmitter is factory
characterized according to the specification. Mount-
ing position effects or zero shifts caused by static
pressure are typically compensated by a zero adjust-
ment.
A span adjustment is a function to correct the slope
error from a zero point in characterizing 100% point
(HRV). This function can be used when span drifts
may be caused or characterization to the specific
pressure standard is required.
Therefore, the zero point adjustment should always
be performed before the upper point adjustment in
order to maintain the pitch between zero and 100%
points within the calibration range.
You can manually perform the trimming procedure
by using J15: SPAN ADJ.