IM 01E20D01-01E
5-9
5. MAINTENANCE
NOTE
• If the hardware switch is set to “Protect,” it will
not be possible to overwrite parameters;
furthermore, this condition will be maintained
until the switch is set to “Enable.”
• In the case of Fieldbus communication type,
setting of the hardware switch (Enable or
Protect) is ineffective and write protection can
be carried out only by software parameter
settings.
For more details regarding usage of the write protect
function and the software’s parameter switches, refer
to “Parameter Description” in the user’s manual of
the AXF Integral Flowmeter [Software Edition]
(IM 01E20C02-01E).
5.6 Regular Inspection
Items
(1) Inspection of moisture-proofing inside the
terminal box: Once/year
(2) Retightening of piping joint screws: About
twice/year
(3) Inspection of electrodes and lining (in
case of adhesive and/or abrasive fluids,
etc.)
Determine the period of regular inspection as
necessary.
5.7 Excitation Coil and
Insulation Resis-
tance Check (Remote
Flowtube Only)
WARNING
• Before checking of the excitation coil and the
insulation resistance, be sure that the power
supply for AXFA11 or the AXFA14 converter
has been turned off.
• Before checking, be sure to disconnect the
cables from the terminals of the remote
flowtube.
(1) Excitation Coil Check (Remote Flowtube
Only)
Check that there is continuity between terminals EX1
and EX2 in the terminal box. If there is no continuity,
the coils may be broken and replacement or repair of
the flowtube is necessary. The coil resistance is
designed to be 150
or less. If it is not, this may be
an abnormal condition. Consult Yokogawa’s sales or
service offices.
(2) Insulation Resistance Check (Remote
Flowtube Only)
Check the insulation resistances in the terminal box in
accordance with the tables below. If any of them falls
below the values listed in the tables, consult
Yokogawa’s sales or service offices for investigation.
If the insulation resistance cannot be restored, replace-
ment or repair of the flowtube is needed. In case of
submersible type flowmeters, undo the wiring connec-
tion on the converter side and measure resistance at the
cable terminals.
Coil Circuit
Checking is possible even if the pipe is filled with
fluid.
Test Terminals
Test Voltage
Specification
500 V DC (Use an insulation
tester or the equivalent.)
1 M
or more
Between terminals
EX1 and C
T050601.EPS
Signal Circuit
Before testing, be sure to empty and dry the interior of
the pipe, checking that there is no adhesive material.
Also undo the wiring connection on the converter side
before testing.
Test Terminals
Test Voltage
Specification
Between terminals
A and C
Between terminals
B and C
500 V DC (Use an insulation
tester or the equivalent.)
100 M
or
more for each
T050602.EPS
5.8 Maintenance of the
LCD Display
CAUTION
The LCD display has certain lifespan and it may
deteriorate during operation. Please contact
Yokogawa office in this case.
