Omron Programmable Terminals NT31 NT31C - Manual (Page 256)

7-4 Section Inspection and Cleaning
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.
Point
Inspected
Inspection Details Criterion
Inspection
Instrument
Power supply
voltage Fluctuation in power supply terminal
voltage Permissible voltage fluctuation range
(24 VDC −15% to +10%)
Tester
Ambient
environmental
di i
Ambient temperature (temperature in the
operation panel) 0 to 50
_C Thermometer
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
diti
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:
Brightness is halved after about
25,000 hours in use at medium
brightness, or about 10,000 hours in
use at high brightness.
Visual inspection
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.
Reference: Desire on replacing the NT31/NT31C
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.