Yokogawa EJX210B - Manual (Page 56)

<8. Setting Parameters>
8-21
IM 01C27C01-01EN
b. To match current input and output value,
follow procedure
Like tank level measurement that is
impossible to set actual level to zero, output
value is adjustment to actual level by other
measurement using glass gauge.
This is an adjustment procedure example.
Conditions are as follows, measurement span
is 0 kPa to 25.00kPa, current level is 13.50kPa,
current output is 13.83kPa.
• Procedure to call up the lower limit
adjustment parameter (Calibration Lowest
Point).
AI1 block : Calibration Lowest Point
Set the actual level value of 13.50 kPa to the
Calibration Lowest Point parameter for the
differential pressure (AI1 block). Apply an
actual input and confirm the value specified
in Calibration Lowest Point as the output
value.
• Procedure to call up the calibration
adjustment parameter (Cal Cmd).
AI1 block : Cal Cmd : CAL_LOW
The present output is changed from 13.83
kPa to 13.50 kPa in CAL_LOW of the
differential pressure (AI1 block) Cal Cmd
parameter.
• Procedure to call up the calibration status
parameter (Cal Status).
AI1 block : Cal Status
Confirm the value of CAL_SUCCESS (1)
using the Cal Status parameter.
DPharp
F0806.ai
25.00 kPa
0.00 kPa
Actual level
13.50 kPa
DPharp span: 0~25.00 kPa
Actual level: 13.50 kPa
Transmitter output: 13.83 kPa
Figure 8.3 Tank level measurement
c. Using External Zero-adjustment Screw
External Zero-adjustment parameter (External
Zero Trim) can set permission or prohibition to
adjustment by External Zero-adjustment Screw.
Set “Trim on” to use the External Zero-
adjustment Screw. (“Trim on” at shipment)
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.
Zero-adjustment Screw
F0807.ai
Figure 8.4 Zero-adjustment Screw