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•
Wiping with a chemical cloth or with volatile solutions such as benzine or
thinner may cause degeneration. A little alcohol may be used if necessary.
•
Prolonged contact with rubber, vinyl products, or tape may leave marks.
•
The PT’s liquid crystal display and backlight can wear out. If they become
hard to see, replace the PT. The backlight of the NT20M-DT121-V2 or
DN121-V2 cannot be replaced.
•
The standard inspection period is once every 6 to 12 months, but it should
be moved up if the operating environment is harsh. If there is any deviation
from the criterion, then it should be corrected.
Inspection item
Inspection content
Criterion
Method/tools
Power supply
Measure at the power supply terminal block. Are
voltage fluctuations within the criterion?
Voltage fluctuation range:
NT20M: 20.4 to 26.4 VDC
NT2000M: 85 to 264 VAC
Tester
Operating
environment
Is the ambient temperature (the temperature inside of
the panel) suitable?
NT20M: 0
°
C to 45
°
C
NT2000M: 0
°
C to 50
°
C
Thermometer
Is the ambient humidity (the humidity inside of the
panel) suitable?
35% to 85% There should
be no condensation.
Hydroscope
Is dust collecting?
There should be no dust.
Visual
Installation
Is each Terminal firmly secured?
There should be no loose
screws.
Phillips
screwdriver
Are the connectors for the connecting cable inserted
perfectly and locked?
There should be no loose
screws.
---
Are any screws for the external wiring coming loose?
There should be no loose
screws.
Phillips
screwdriver
Is any external wiring loose or disconnected?
There should be no external
abnormalities.
Visual
Replaceable
parts
Can you read the characters on the liquid crystal
display?
Is the backlight illumination as bright as it should be?
Average life expectancy of
liquid crystal:
50,000 hrs
Average life expectancy of
backlight:
20,000 hrs
Visual
Precautions for Handling
•
Turn off the power before replacing a PT.
•
When you discover what seems to be a defective PT, check it again before
replacing it to be sure that the problem is actually with the PT.
•
When returning a defective PT for service, please describe the problem in
as much detail as possible. Send the PT to the OMRON office closest to
you.
Tools for Inspection
•
Phillips and flat-blade screwdrivers
•
Voltage tester or digital voltmeter
•
Industrial alcohol and all-cotton cloth
Measuring Instruments (Depending on Case)
•
Synchroscope
•
Oscilloscope with pen output
•
Thermometer
•
Hydroscope
Maintenance and Inspection
Section 8-4