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Inspection and Cleaning
Section 7-4
• Faulty Display Pixels
Although the LCD panel has been manufactured with extremely high-level
technology, there can sometimes be pixels that will not light or that will be
lit constantly. These are characteristic of LCD panels and are not an indi-
cation of a faulty display. Please understand that, although we are con-
stantly striving to keep these pixels to a minimum, it is not possible with
present technology to eliminate them completely.
• 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 NT20.
Note
(1) Do not attempt to disassemble the NT20 for repair or modification.
(2) The disposal of the NT20 may be regulated by national or local authori-
ties. Dispose of them according to the laws and regulations of the relevant
country and local authority.
(3) When replacing the NT20 after discovering a fault during inspections,
note the following points:
• Be sure to switch the power OFF before replacement.
• After replacement, check that the new NT20 is not subject to the same
error.
• 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 address indicated on the back cover of this book.
Point Inspected
Inspection Details
Criterion
Inspection Instrument
Power supply voltage
Fluctuation in power supply terminal volt-
age
Permissible voltage fluc-
tuation range (24 VDC
−
15% +15%)
Tester
Ambient environmen-
tal conditions
Ambient temperature (temperature in the
operation panel)
0 to 50
°
C
Thermometer
Ambient humidity
(humidity in the operation panel)
35% to 85%
Hygrometer
Presence/absence of dust
Dust must not be settled
Visual inspection
Mounting conditions
Looseness of mounting brackets etc.
To be no looseness
Accessory tools
Connector connections of connecting cable To be fully inserted and
locked, with no loose-
ness
Looseness of screws in external wiring
To be no looseness
Phillips screwdriver
Conditions of external connecting cables
Faults such as incipient
disconnections.
Visual inspection
External appearance
Peeling of front sheet
Front sheet must not
show any signs of peel-
ing.
Visual inspection
Summary of Contents for NT20
Page 1: ...Programmable Terminal Cat No V091 E1 01 NT20 USER S MANUAL ...
Page 2: ...NT series Programmable Terminal User s Manual Produced March 2007 ...
Page 3: ...iv ...
Page 5: ...vi ...
Page 9: ...x TABLE OF CONTENTS ...
Page 15: ...xvi ...
Page 21: ...xxii EC Directives 6 ...
Page 37: ...16 Before Operating Section 1 6 ...
Page 153: ...132 Transferring the Resource Data Section 3 11 ...
Page 185: ...164 Numeral Setting Section 4 8 ...
Page 267: ...246 Key to Programs Section 6 8 ...
Page 281: ...260 Specifications Appendix A ...
Page 285: ...264 Transporting and Storing PTs Appendix C ...
Page 303: ...282 Function Restrictions Depending on the Support Tool Appendix I ...
Page 307: ...286 Index ...
Page 309: ...288 Revision History ...