Manual

<10. Maintenance>
10-1
IM 01S01C01-01EN
10. Maintenance
10.1 Overview
Maintenance of the indicator is easy due to its
modular construction. This chapter describes the
procedures for the disassembly and reassembly
procedures required for component replacement.
Indicators are precision instruments. Please
carefully and thoroughly read the following sections
for information on how to properly handle them
while performing maintenance.
IMPORTANT
• As a rule, maintenance of this indicator
should be done in a shop that has all the
necessary tools.
• The CPU assembly contains sensitive parts
that can be damaged by static electricity.
Take precautions such as using a grounded
wrist strap when handling electronic parts or
touching the board circuit patterns. Also be
sure to place the removed CPU assembly
into a bag with an antistatic coating.
10.2 Disassembly and
Reassembly
This section describes procedures for disassembly
and reassembly for maintenance and component
replacement.
Always turn OFF power and shut off and release
pressures before disassembly. Use proper tools for
all operations. Table 10.1 shows the tools required.
Table 10.1 Tools for Disassembly and Reassembly
Tool Quantity Remarks
Phillips
screwdriver
1 JIS B4633, No. 2
Slotted
screwdriver
1
Allen wrenches 3 JIS B4648
One each, nominal 3, 4 and
2.5 mm Allen wrenches
Socket driver 1 Width across ats, 5.5 mm
Tweezers 1
CAUTION
Precautions for ATEX Flameproof Type
Indicators
• Flameproof type indicators must be, as a
rule, removed to a non-hazardous area for
maintenance and be disassembled and
reassembled to the original state.
• On the ameproof type indicators the two
covers are locked, each by an Allen head bolt
(shrouding bolt). When a shrouding bolt is
driven clockwise by an Allen wrench, it is going
in and cover lock is released, and then the
cover can be opened.
When a cover is closed it should be locked
by a shrouding bolt without fail. Tighten the
shrouding bolt to a torque of 0.7 N·m.
Shrouding Bolt
F1001.ai
Figure 10.1 Shrouding Bolts
10.2.1 Replacing the display
CAUTION
Cautions for Flameproof Type Indicators
Users are prohibited by law from modifying the
construction of a ameproof type indicator. This
would invalidate the agency approval for the use
of the indicator in a rated area.
It follows that the user is prohibited from using
a ameproof type indicator with its display
removed, or from adding an display to a
indicator. If such modication is absolutely
required, contact Yokogawa.
This subsection describes the procedure for
replacing an display. (See gure 10.2)