Omron Programmable Terminals NT631 Setup Manual page 260

Inspection and Cleaning
Inspection Method
Point
Inspected
Power supply Fluctuation in power supply terminal
voltage voltage
Ambient envi- Ambient temperature (temperature in
ronmental con- the operation panel)
ditions
Ambient humidity (humidity in the
operation panel)
Presence/absence of dust
Mounting condi- Looseness of mounting brackets, etc.
tions
Connector connections of connecting
cable
Looseness of screws in external wir-
ing
Conditions of external connecting
cables
Components Brightness of the backlight
with limited lives (NT631C only)
Note
In normal environments, inspect the NT631/NT631C at intervals of between 6
months and a year. In environments that are extremely hot and humid, or very
dusty environments, shorten the inspection interval.
Items Required for The Inspection
Prepare the following items before starting the inspection.
• Screwdrivers (Phillips, flat head)
• Tester (or digital voltmeter)
• Industrial alcohol
• 100% cotton cloth
• Hygrometer (required in some cases)
• Thermometer (required in some cases)
• Synchroscope (required in some cases)
• Pen-writing oscilloscope (required in some cases)
Points Inspected
Inspect the following points to determine if there is any divergence from the
stated criteria. If there is, either improve the surrounding environment so that
the values fall within the stated range, or adjust the NT631/NT631C, for exam-
ple by re-tightening screws.
Inspection Details
1. Do not disassemble for repairs or modification.
Criterion
Permissible voltage fluctuation range
20.4 to 26.4 VDC (24 VDC –15% to
+10%)
0 to 50°C
35% to 85% RH
Dust must not be settled
To be no looseness
To be fully inserted and locked, with no
looseness
To be no looseness
Faults such as incipient disconnection
Must be sufficiently bright.
Backlight life:
(Under the normal range of ambient tem-
perature and humidity)
NT631C-ST141@-EV2: Approx.
25,000 hours or longer
NT631C-ST151@-EV2: Approx.
30,000 hours or longer
NT631C-ST152@-EV2/ST153@-EV3:
Approx. 50,000 hours or longer
(Brightness setting is not available for
the NT631C-ST151/152@-EV2/
ST153@-EV3 and the backlight can-
not be replaced.)
Section 7-4
Inspection
Instrument
Tester
Thermometer
Hygrometer
Visual inspection
Phillips screwdriver
Phillips screwdriver
Phillips screwdriver
Visual inspection
Visual inspection
243