Omron NT20, Руководство пользователя

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185
Memory Tables and Bar Graphs Section 5-2
Here, the method for changing the display using method 1) is explained. For
details on method 2), refer to the explanations on direct specification on
page 182 and
5-2-4 Copying Memory Table Entries on page 186.
Note This method is convenient when switching the display at the same location, for
example when monitoring a series of words, or when using unique codes to
specify individual character strings, etc.
1,2,3... 1. Set the PLC area for allocation of the numeral memory table entry to be
referenced in indirect specification using the Support Tool.
2. When using the Support Tool to create screen data, register on the screen
the numeral memory table entry referenced in indirect specification. Spec-
ify the “indirect” option for the reference method.
In the case of a character string, use the “character display” function of the
Support Tool to specify the numeral memory table entry.
In the case of a numerical value, use the “numeral display” function of the
Support Tool to specify the numeral memory table entry.
3. Use the “table edit” function of the Support Tool to write the actually dis-
played data to the memory table entry for display. If displaying a numerical
value, use a numeral memory table entry and if displaying a character
string use a character string memory table entry.
4. Create a PLC program to change the contents of the word allocated to the
numeral memory table referenced in the indirect specification.
• Precautions on Writing Memory Table Entry Numbers
When writing the number of the memory table for display to the numeral
memory table entry referenced in indirect specification, always specify it in
BCD. Also, be sure to specify a number within the range of memory table
entry numbers that actually exist (0 to 127).
If the contents of the numeral memory table entry for indirect specification
are specified in hexadecimal format, or the number specified is outside the
valid range for memory table entry numbers, the display is not updated.
• Precautions on Writing Character Strings
The points to note when displaying character strings are the same as those
described for direct specification. Refer to
Important points when writing a
character string to page 149.
Example Use of Indirect Specification
This example shows a case where the displayed character string is changed
by incrementing the contents of the allocated word of the numeral memory
table entry referenced in indirect specification.
• Settings with the Support Tool
Make the following settings with the Support Tool.
NT20 PLC
AaBb 0039
AaBb
Moji
0 3 0 9
0039
Indirect numeral memory
table entry 41
Character string
memory table entry 39
Character string memory
table entry 40
Allocated word (numeral
memory table entry 41)