Yokogawa EJA530A - Manual (Page 52)

IM 01C21F01-01E 9-3
9. MAINTENANCE
9.4 Disassembly and Reassem-
bly
CAUTION
Precautions for CENELEC and IECEx Flame-
proof Type Transmitters
• Flameproof type transmitters must be, as a
rule, removed to a non-hazardous area for
maintenance and be disassembled and reas-
sembled to the original state.
• On the flameproof type transmitters 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 by hand.
When a cover is closed it should be locked by a
shrouding bolt without fail. Tighten the shroud-
ing bolt to a torque of 0.7 N·m.
This section describes procedures for disassembly and
reassembly for maintenance and component replace-
ment.
Always turn OFF power and shut off and release
pressures before disassembly. Use proper tools for all
operations. Table 9.4.1 shows the tools required.
Table 9.4.1 Tools for Disassembly and Reassembly
Tool Remarks Quantity
Phillips screwdriver
Slotted screwdriver
Allen wrenches JIS B4648
One each, nominal 3 and
5 mm Allen wrenches
Wrench
Torque wrench
Adjustable wrench
Socket wrench
Socket driver
Tweezers
1
1
2
1
1
1
1
1
1
JIS B4633, No. 2
Width across flats, 17 mm
Width across flats, 16 mm
Width across flats, 5.5 mm
T0902.EPS
Shrouding Bolt
Shrouding Bolt
F0902.EPS
Figure 9.4 Shrouding Bolts
9.4.1 Replacing the Integral Indicator
CAUTION
Cautions for Flameproof Type Transmitters
Users are prohibited by law from modifying the
construction of a flameproof type transmitter.
This would invalidate the agency approval and
the transmitter’s use in such rated area.
Thus the user is prohibited from using a flame-
proof type transmitter with its integral indicator
removed, or from adding an integral indicator to
a transmitter. If such modification is absolutely
required, contact Yokogawa.
This subsection describes the procedure for replacing
an integral indicator. (See Figure 9.4.1)
᭿ Removing the Integral Indicator
1) Remove the cover.
2) Supporting the integral indicator by hand, loosen its
two mounting screws.
3) Dismount the LCD board assembly from the CPU
assembly.
When doing this, carefully pull the LCD board
assembly straight forward so as not to damage the
connector pins between it and the CPU assembly.