IM 01C25F01-01E
7-3
7. OPERATION
(2) When you cannot obtain the Low Range
Value from the actual measured value of 0%;
Adjust the transmitter output to the actual measured
value obtained by a digital manometer or a glass
gauge.
[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%
(=10.4mA)
Turn the screw to match the output signal to the actual
measured value.
7.3 Starting Operation
After completing the zero point adjustment, follow the
procedures below to start operation. Steps 1) and 2) are
specific to the differential pressure transmitters.
1) Confirm the operating status. If the output signal
exhibits wide fluctuations (hunting) due to periodic
variation in the process pressure, use the communi-
cator to dampen the transmitter output signal.
Confirm the hunting using a receiving instrument or
the integral indicator, and set the optimum damping
time constant.
2) After confirming the operating status, perform the
following.
IMPORTANT
• Remove the communicator from the terminal
box, and confirm that none of the terminal
screws are loose.
• Close the terminal box cover and the amplifier
cover. Screw each cover in tightly until it will
not turn further.
• There are two covers that must be locked on
the ATEX Flameproof type transmitters. An
Allen head bolt (shrouding bolt) under the edge
of each cover is used to lock the cover. When
the shrouding bolt is driven counterclockwise
with an Allen wrench, the bolt rotates upward
and locks the cover. (See section 8.4) After
locking the covers, confirm that they are secure
and cannot be opened by hand.
Tighten the zero-adjustment cover mounting
screw to secure the cover.
• Tighten the zero-adjustment cover mounting
screw to secure the cover.
7.4 Shutting Down the Transmitter
Shut down the transmitter as follows.
Steps 2) and 3) are specific to the differential pressure
transmitters.
1) Turn off the power.
2) Close the stop valve.
3) Open the equalizing valve.
4) Close the high pressure stop valve.
5) Close the tap valve.
NOTE
• Whenever shutting down the transmitter for a
long period, remove any process fluid that is in
the transmitter pressure-detector section.
• The equalizing valve must be left OPEN.
7.5 Setting the Range Using the
Range-setting Switch
WARNING
The range setting switch must not be used in the
hazardous area.
When it is necessary to use the switch, operate
it in a non-hazardous location.
When pressure is applied to the transmitter, the low-
and high-limit values for the measurement range (LRV
and URV) can be changed (re-ranged) using the range-
setting switch (push-button) located on the optional
integral indicator plate and the external zero adjustment
screw. This procedure does not require use of the
communicator. However, changes in the scale range
and engineering unit display settings for the integral
indicator require use of the communicator.
Follow the procedure below to change the LRV and
URV settings.
[Example]
Rerange LRV to 0 and URV to 3 MPa.
1) Connect the transmitter and apparatus as shown in
Figure 8.1 and warm it up for at least five minutes.
2) Press the range-setting push-button.
The integral indicator then displays “
LRV.SET
.”
3) Apply a pressure of 0 kPa (atmospheric pressure) to
the transmitter.
(Note 1)
