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Notification of the Operating Status to the PLC (Determining the NT20 Operating Status)
Section 5-5
5-5
Notification of the Operating Status to the PLC
(Determining the NT20 Operating Status)
The status (operating status, etc.) of the NT20 can be determined from the
PLC by reading the “PT status” word in the PT status notify area allocated in
the PLC memory.
5-5-1
Ascertainable NT20 Status (Notified Operating Status)
PT Status Notification Bits of the PT Status Notify Area
!Caution
Make the settings so that the PT control area and PT status notify area do not
overlap.
• PT Operating Status (Bit 15)
When the NT20 is in the RUN mode this bit is set to ON (1). In other modes
and while the system menu is displayed it is OFF (0). When this bit is OFF
allocated bits and words cannot be read or written to.
During the run mode, ON (1) is periodically written into this bit. In order to
check whether the NT20 is operating normally or not, write OFF (0) to this
bit: if it is ON (1) 30 seconds later the NT20 is running, and if it is OFF (0),
the NT20 is stopped.
!Caution
To ensure system safety, be sure to periodically read the PT operating status
bit from the host in order to ensure that the PT is always operating normally.
NT20
PLC
PT stopped
PT status notify area
Currently displayed screen
Upgraded memory table entry
PT status
Screen
number
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Bit
0 0 0 0 0
Word
m+2
15 14 13 12 11 10 9 8 Bit
PT status notification bits
0 0
PT status
PT operating status
(1(ON) = operating / 0 (OFF) = stopped)
Screen switch strobe flag
Numeral setting strobe flag
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 ...