Yokogawa EJA530A - Manual (Page 30)

IM 01C21F01-01E 7-3
7. OPERATION
7.2.2 When you cannot obtain Low Range
Value from actual measured value
of 0%;
Convert the actual measured value obtained by a digital
manometer or a glass gauge into %.
[Example]
The measuring range of 50 to 250 kPa; the actual
measured value of 130 kPa.
130–50
250–50
Actual measured value= x 100=40.0%
᭿ Using the Transmitter Zero-Adjustment Screw
Turn the screw to match the output signal to the actual
measured value in %.
᭿ Using the BT200
Select the parameter J10: ZERO ADJ. Change the
set point (%) displayed for the parameter to the actual
measured value (%), and press the ENTER key twice.
See Subsection 8.3.3 (11) for operation details.
Change setting to the actually
measured value (40.0%).
Press key twice
for 40% output 10.4 mA DC.
SET
J10:ZERO ADJ
–0.0 %
+ 040.0
CLR ESC
F0706.EPS
Display at J10 SET
J10:ZERO ADJ
–0.0 %
+ 000.0
CLR ESC
7.3 Starting Operation
After completing the zero point adjustment, follow the
procedure below to start operation.
1) Confirm the operating status. If the output signal
exhibits wide fluctuations (hunting) due to periodic
variation in the process pressure, use BT200 to
dampen the transmitter output signal. Confirm the
hunting using a receiving instrument or the integral
indicator, and set the optimum damping time
constant. See Subsection 8.3.3 (3), “Damping Time
Constant Setup.”
2) After confirming the operating status, perform the
following.
IMPORTANT
• Remove the BT200 from the terminal box, and
confirm that none of the terminal screws are
loosened.
• Close the terminal box cover and the amplifier
cover. Screw each cover in tightly until it will
not turn further.
• Two covers are required to be locked on the
CENELEC and IECEx Flameproof type trans-
mitters. An Allen head bolts (shrouding bolts)
are provided under edge of the each cover for
locking. When a shrouding bolts are driven
counterclockwise by an Allen wrench, it is
coming out and locks up a cover. (See page 9-
4) After locking, the covers should be con-
firmed not to be opened by hands.
• Tighten the zero-adjustment cover mounting
screw to fix the cover in position.
7.4 Shutting Down Operation
Shut down the transmitter operation as follows.
1) Turn off the power.
2) Close the stop valve.
3) Close the tap valve.
NOTE
Whenever shutting down the transmitter for a
long period, remove any process fluid from the
transmitter pressure-detector section.