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7-4
Section
Inspection and Cleaning
186
Point
Inspected
Inspection Details
Criterion
Inspection
Instrument
Power supply
voltage
Fluctuation in power supply terminal
voltage
Permissible voltage fluctuation range
(24 VDC
−
15% to +15%)
Tester
Ambient
environmental
Ambient temperature (temperature in the
operation panel)
0 to 50
_
C
Thermometer
e
o
e ta
conditions
Ambient humidity (humidity in the
operation panel)
35% to 85% RH
Hygrometer
Presence/absence of dust
Dust must not be settled
Visual inspection
Mounting
di i
Looseness of mounting brackets, etc.
To be no looseness
Philips screwdriver
g
conditions
Connector connections of connecting
cable
To be fully inserted and locked, with
no looseness
Philips screwdriver
Looseness of screws in external wiring
To be no looseness
Philips screwdriver
Conditions of external connecting cables
Faults such as incipient disconnection
Visual inspection
Components
with limited
lives
Brightness of the backlight
Must be sufficiently bright.
Backlight life:
At normal ambient temperature and
humidity, the backlight brightness will
drop to about 50% of its original
brightness after 50,000 hours of use.
Visual inspection
Note
1. Do not disassemble for repairs or modification. Otherwise the product may
malfunction.
2. The disposal of the Unit and spent batteries may be regulated by national or
local authorities. Dispose of them in accordance with the laws and regula-
tions of the relevant country and local authority.
Reference: Desire on replacing the NT21
When replacing the NT21 after discovering a fault during inspections, note the
following points:
S
Be sure to switch the power OFF before starting replacement.
S
After replacement, check that the new NT21 is not subject to the same error.
S
If a faulty Unit is returned for repairs, write as detailed a description of the fault
as possible and send this description together with the Unit to the OMRON ad-
dress indicated on the back cover of this book.