Yokogawa EJA115 - Manual (Page 31)

IM 01C22T03-00E 6-1
6. CALIBRATION
6. CALIBRATION
6.1 Zero-point adjustment
Zero-point adjustment can be performed in two ways.
Choose the optimum method in accordance with the
circumstances specific to the application employed.
(a) Using FieldMate
In the DTM Works window, click [Device]
→
[Con-
nect]
Click [Device]
→
[Parameter]
→
[Online Parameter]
Click the [Calibration] folder.
Perform the following procedure to set the current
output value to 0%.
Change Target Mode to [Out of Service].
Change Trim Mode to [Trim enable].
Set the input pressure to zero.
Set Trim PV Zero to zero.
Change Trim Mode to [Trim disable].
Figure 6.1 Zero-point adjustment
(b) Using the transmitter zero-adjustment
screw
In the DTM Works window, click the [Calibration]
folder Confirm External Zero Enable is set to [Enable].
Set the input pressure to zero.
Turn the zero-adjustment screw on the outside of the
transmitter case using a screwdriver. Turning the screw
clockwise causes the output value to increase while
turning it counterclockwise cause the output to de-
crease; zero-point can be adjusted with a resolution of
0.001% of range setting.
The amount of zero-point adjustment changes accord-
ing to the speed at which the zero-point screw is
turned; turn it slowly for fine tuning, or quickly for
rough tuning.
6.2 Sensor calibration of EJA
while applying actual inputs
Sensor calibration is carried out in two steps: first the
lower sensor is calibrated, then the upper sensor is
calibrated. The sensor calibration is a two-point
adjustment and the lower point adjustments 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.
6.2.1 Setting procedure
Example: For the range of 0 to 110kPa
Change the Trim Mode to [Trim enable].
Apply a standard pressure of 0kPa to the transmitter.
Set the Lower Calibration Point to 0kPa.
Apply a standard pressure of 110kPa to the transmitter.
After obtaining a stable pressure, set the Upper
Calibration Point to 110kPa.
Change the Trim Mode to [Trim disable].
Figure 6.2 Sensor calibration while applying actual inputs