Yokogawa EJX530B - Manual (Page 30)

<7. Operation>
7-2
IM 01C27F01-01EN
 Verify and Change Transmitter
Parameter Setting and Values
The parameters related to the following items are
minimum required to be set for operation, and set at
factory as specified in order. Confirm or change the
parameters if needed.
• Measurement range (measurement lower/
upper limit, unit)
7.2 Zero Point Adjustment
After completing preparations for operating the
transmitter, adjust the zero point. There are two
zero point adjusting ways.
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.
(1) When you can obtain the Low Range Value
from the actual measured value of 0%
(0kPa, atmospheric pressure);
 Using the transmitter’s zero-adjustment
screw
Before adjusting zero point, make sure followings.
• That the External zero trim parameter
(External Zero Trim) is “Trim on”. For details,
refer to section 8 “Setting Parameters”.
• 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. The
degree of zero adjustments varies with the screw
turning speed turn the screw slowly to make a fine
adjustment, quickly to make a rough adjustment.
 Using the Device Configuration Tool
Refer to subsection 8.3.10 “Zero Point Adjustment
and Span Adjustment”.
(2) When you cannot obtain the Low Range
Value from the actual measured value of
0%;
Adjust the transmitter output value matches to
the actual measured value obtained by precise
pressure measurement equipment.
[Example]
The measuring range of 50 to 250 kPa : the actual
measured value of 130kPa.
130–50
250–50
Actual measured value= x100=40.0%
 Using the transmitter’s zero-adjustment
screw
Turn the zero adjustment screw to match the output
signal to the actual measured value.
 Using the Device Configuration Tool
Refer to subsection 8.3.10 “Zero Point Adjustment
and Span Adjustment”.
7.3 Starting Operation
After the zero point adjustment is completed, the
transmitter is already the operating status. Follow
the procedure below.
1) Confirm the operating status.
2) After confirming the operating status, perform
the following.
IMPORTANT
• Close the terminal box cover and the
amplifier cover. Screw each cover in tightly
until it will not turn further.
• Tighten the zero-adjustment cover mounting
screw to secure the cover.