Omron Programmable Terminals NT31 NT31C Setup Manual page 256

Inspection and Cleaning
Point
Inspected
Power supply Fluctuation in power supply terminal
voltage voltage
Ambient Ambient temperature (temperature in the
environmental operation panel)
conditions di i
Ambient humidity (humidity in the
operation panel)
Presence/absence of dust
Mounting g Looseness of mounting brackets, etc.
conditions diti
Connector connections of connecting
cable
Looseness of screws in external wiring
Conditions of external connecting cables Faults such as incipient disconnection Visual inspection
Components Brightness of the backlight
with limited
lives
Reference: Desire on replacing the NT31/NT31C
246
• 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 NT31/NT31C, for example by
re-tightening screws.
Inspection Details
Note 1. Do not disassemble for repairs or modification.
2. The disposal of the unit (including batteries to be disposed and backlight)
may be regulated by national or local authorities. Dispose of them in accor-
dance with the laws and regulations of the relevant country and local author-
ity.
When replacing the NT31/NT31C 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 NT31/NT31C 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.
Criterion
Permissible voltage fluctuation range
(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
Must be sufficiently bright.
Backlight life:
Brightness is halved after about
25,000 hours in use at medium
brightness, or about 10,000 hours in
use at high brightness.
Section 7-4
Inspection
Instrument
Tester
Thermometer
Hygrometer
Visual inspection
Philips screwdriver
Philips screwdriver
Philips screwdriver
Visual inspection