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D-160TS-7-E
39
19. MAINTENANCE
This flowmeter is manufactured and inspected under stringent quality control program before leaving the
factory. As long as the flowmeter is used under proper conditions, its performance will remain stable. In
cases of trouble, check the items listed in the below table.
19.1 Check Items
19.2 Probe (sensor) Inspection
Sensor inspection should be performed with power turned off.
(
1
)
Sensor resistance measurement
Remove sensor leads (2 white, 1 red (black)) inside the terminal box on the meter side and make a
sensor resistance measurement with an ohmmeter or equivalent.
Fig. 19.1
Rated resistance value (23
℃
±5
℃
)
Resistors
(
R1
、
R2
)=
10kΩ ± 3kΩ
Sensor dispersion
(
R1
>
R2
)
※
1
:
Polarity observation is not required for two white sensor leads.
※
2
:
Sensor resistance value varies with temperature.
WH
RD
WH
Sensor leads
R1
R2
(BK)
R1 - R2
R2
≦
0.05
SYMPTOM
CHECK ITEM
SECTION TO
BE
REFERRED TO
○
○
①
Is the wiring appropriate? (sensor-converter, converter-receiving instrument )
8.1
、
8.2
○
○
②
Is power supplied?
8.1
、
19.3
○
③
Are block valves (A, B, C) open?
9
○
④
Is the gas to be measured flowing?
—
○
○
⑤
Does the receiving instrument have proper specifications (e.g. input pulse width)
21
(
2
)
○
○ ⑥
Are there any leaks from piping, valves, etc.?
—
○
○ ⑦
Is the flow rate proper (within the flow range)?
21
(
3
)
○
○
○ ⑧
Is there inductive interference from power equipment?
8.1
、
8.2
○
○
○ ⑨
Is there pulsation in the line (from a pump, compressor, etc.)?
6.8
○
○
○ ⑩
Is mist (moisture) adhered on the sensor?
19.2
○ ⑪
Is the bypass line completely shut off?
—
○
○
⑫
Are piping conditions appropriate (e.g. meter center not aligned,
insufficient upstream pipe) ?
6.1
、
6.2
、
6.3
6.4
、
6.5
○ ⑬
Is the flow rate conversion done correctly (e.g. normal rate conversion)?
—
○
○ ⑭
Are fluid conditions proper (e.g. pressure, temperature)?
21
(
1
)
○ ⑮
Is the reference meter correct?
—
○
○
○
○ ⑯
Is there any malfunction with the sensor?
19.2
○
○
○
○ ⑰
Is there any malfunction with the converter?
18
、
19.3
Significant
err
ors
Unstable indication
Erratic output with no flow
No output
Does not start up
Applicable to software ver. 1.11 or later.