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Communications Time
2) Fast mode
1 8 0
T A T
( m s )
1 6 0
1 4 0
1 2 0
1 0 0
8 0
6 0
4 0
2 0
0
1
3) Actual Communications Time in Multiple, Simultaneous Access Mode
The actual communications time between the Controller and Tag using commands for multiple access
varies with the operating conditions, such as the number of Tags in the communications area as well
as the number of bytes to be processed.
Refer to the following table for standard values in consideration of these conditions.
Number of
Timeslot setting
Tags
2
1
4
2
8
3
16
4
4) Calculation of TAT
TAT can be calculated by adding the host communications time to the actual communications time.
The host communications time varies depending on the communications settings and the codes that
you specify.
Example of calculation: when operating in Single Access Mode and Trigger Mode to read 1 page (4
bytes) data
Code-specified in ASCII:
The total number of characters is 29, i.e., 15 characters in the command part and 14 characters in the
response part. From this, the host communications time would be 29 * 11 bits /38400(bps) * 1000 = 8.3 (ms).
The communications time would be14 ms for Fast Mode and 92.9 ms for Standard Mode. TAT, therefore,
would be 8.3 + 14 = 22.3 ms for Fast Mode and 8.3 + 92.9 = 101.2 ms for Standard Mode.
Code-specified in HEX:
Writing
Reading
Special reading
2
3
4
5
6
7
8
9
Number of pages processed
Calculation Formula
Special reading
Read
Write
N: Number of pages processed
Note • The provided TAT graph data shows an example in which the
V720S-BC5D4 Controller is used with the following communications
specifications for host communications: The data is continuously sent with
no space between characters, at a baud rate of 38,400 bps, in a data length
of 7 bits with 1 start bit, 2 stop bits and even parity.
• The number of bytes in TAT data is the number of code-specified bytes in
ASCII.
2 pages (8 bytes) to read (ms)
Standard mode
560
917
1659
3239
1 8 0
Actual
1 6 0
communicat
1 4 0
ions time
(ms)
1 2 0
1 0 0
8 0
6 0
4 0
2 0
0
1 0 1 1
1
Actual communications time (ms)
T = 1.3N + 6.2
T = 1.3N + 12.7
T = 13N +13.5
Fast mode
144
301
644
1391
Writing
Reading
Special reading
2
3
4
5
6
7
8
Number of pages processed
(msec)
2 pages (8 bytes) to write (ms)
Standard mode
Fast mode
715
190
1139
378
2016
784
3867
1656
Section 7-1
9
1 0 1 1
(msec)
7-3
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