170
Overview of Direct Connection Operations
Section 5-1
Notification of the Display Elements by Using Allocated Bits and Words
The NT20 will operate as follows in the display element notification operation.
NT20 Operation
The NT20 will write any changes in the contents of the numeral or character-
string memory table entry being displayed or pressing of a touch switch to the
bits and words area in the PLC.
NT20 Operation Example
Notification of the NT20 Status by Using Allocated Bits and Words ..... PT Status Notify Area (PT to
PLC)
The PT status notify area (PT to PLC) is provided to notify the PLC of NT20
status changes. When any NT20 status has changed, such change is written
to this area in the PLC, and the PLC will read the data from this area to check
the NT20 status.
The PT status notify area is configured as three consecutive words as shown
below.
The first word (word m) of the PT status notify area must be set with the Sup-
port Tool.
• Currently Displayed Screen (refer to page 175)
The screen number displayed on the NT20 is written to this word.
Simultaneously, the PT status screen switch strobe flag is set to ON (1).
After the PLC is notified, this flag reverts to OFF (0). Checking the status
of this flag will provide a simple method of checking if the NT20 display has
switched.
• Upgraded Memory Table Entry (Refer to page 200.)
The number of the numeral memory table entry is written to the word when
the numeral memory table contents change due to the touch switch oper-
ation on the NT20.
As the number of the numeral table entry is written, the PT status numeral
setting strobe flag is simultaneously set ON (1). After the PLC is notified,
this flag reverts to OFF (0). Checking the status of this flag will provide a
simple method of checking if a number has been input from the NT20.
Note that this function is not available with the character-string memory ta-
ble.
• PT Status (Refer to page 208.)
The NT20 operation status and other information are written with the ON
or OFF of the bits as shown below.
Numeral memory table entry 100
Copy
Bit 009012: ON
Numeral memory table entry 0
Number of saved words: 1
First word: DM0110
DM0110: 0432
NT20
PLC
0 4 3 2
Touch switch #12
Bit 009012
Screen being displayed
PT status
m
m+1
m+2
Word 15 14 13 12 11 10 9
8 7
6 5 4 3 2
1
0 Bit
0
Screen # (4-digit BCD)
PT status
Numeral memory table entry # (3-digit BCD)
0
0
Upgraded memory
table entry
Содержание NT20
Страница 1: ...Programmable Terminal Cat No V091 E1 01 NT20 USER S MANUAL ...
Страница 2: ...NT series Programmable Terminal User s Manual Produced March 2007 ...
Страница 3: ...iv ...
Страница 5: ...vi ...
Страница 9: ...x TABLE OF CONTENTS ...
Страница 15: ...xvi ...
Страница 21: ...xxii EC Directives 6 ...
Страница 37: ...16 Before Operating Section 1 6 ...
Страница 153: ...132 Transferring the Resource Data Section 3 11 ...
Страница 185: ...164 Numeral Setting Section 4 8 ...
Страница 267: ...246 Key to Programs Section 6 8 ...
Страница 281: ...260 Specifications Appendix A ...
Страница 285: ...264 Transporting and Storing PTs Appendix C ...
Страница 303: ...282 Function Restrictions Depending on the Support Tool Appendix I ...
Страница 307: ...286 Index ...
Страница 309: ...288 Revision History ...