<9. Maintenance>
9-6
IM 01C27F01-01EN
9.4.3 Replacing the CPU Assembly
This subsection describes how to replace the CPU
assembly (see Figure 9.2).
■ Removing the CPU assembly
1) Remove the cover.
Remove the integral indicator and the RF
assembly (refer to subsections 9.4.1 and 9.4.2).
2) Turn the zero-adjustment screw to the position
as shown in Figure 9.2.
3) Disconnect the power cable (cable with brown
connector at the end).
When doing this, lightly press the side of the
CPU assembly connector and pull the cable
connector to disengage (see the upper left of
Figure 9.2).
4) Use a socket driver (width across flats, 5.5 mm)
to loosen the two bosses.
5) Carefully pull the CPU assembly straight
forward to remove it.
6) Disconnect the flat cable (cable with white
connector at the end) that connects the CPU
assembly and the capsule.
NOTE
Be careful not to apply excessive force to the
CPU assembly when removing it.
■ Mounting the CPU assembly
1) Connect the flat cable (with white connector)
between the CPU assembly and the capsule.
2) Connect the power cable (with brown
connector) to the CPU assembly.
NOTE
Make certain that the cables do not get pinched
between the case and the edge of the CPU
assembly.
3) Align and engage the zero-adjustment screw
pin with the groove on the bracket on the CPU
assembly. Then insert the CPU assembly
straight onto the post in the amplifier case.
4) Tighten the two bosses. Mount the RF
assembly, and the integral indicator (refer to
subsections 9.4.1 and 9.4.2).
IMPORTANT
Confirm that the zero-adjustment screw pin is
placed properly in the groove on the bracket prior
to tightening the two bosses. If it is not, the zero-
adjustment mechanism will be damaged.
5) Replace the cover.
9.4.4 Cleaning and Replacing the Capsule
Assembly
CAUTION
Precautions for the intrinsic safety explosion
prevention type instrument
Modification is not permitted by the user for
intrinsic safety explosion prevention type
transmitter. If you wish to replace the capsule
assembly with one of a different measurement
range, contact Yokogawa.
The user is permitted, however, to replace a
capsule assembly with another of the same
specification and measurement range. After
completing maintenance, be sure to securely
tighten the setscrews that fasten the transmitter
section and pressure-detector section together.
This subsection describes the procedures for
cleaning and replacing the capsule assembly. (See
figure 9.3.)
■
Removing the Capsule Assembly
IMPORTANT
Exercise care as follows when cleaning the
capsule assembly.
• Handle the capsule assembly with care, and
be especially careful not to damage or distort
the diaphragms that contact the process
fluid.
• Do not use a chlorinated or acidic solution for
cleaning.
• Rinse with clean water after cleaning, please
dry until completely dry.
