Omron V670-CF01, User Manual, Page: 80 / 92

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Electromagnetic Inductive RFID System
User's Manual
SECTION 6
Appendices
Read and write communications with Tags is performed in 4-byte units. This means that the communi-
cations time can be minimized by specifying the address and number of bytes so that the write start
address is a multiple of 4.
Example: If 4 bytes of data is to be written from address 0001h, change the address to 0000h.
If the system configuration is such that the address cannot be changed like this, the times on the fol-
lowing table must be added to the communications time.
•
TAT
The TAT is the time from the start of command transmission by the host device to the end of response
reception by the Handy Terminal. TAT can be calculated from the communications time and the number
of command/response characters. The formula is shown below.
* The transmission time depends on the number of bits per character and the communications condi-
tions (baud rate, data length, parity, and stop bits).
This formula applies when there is no interval between Handy Terminal command characters, i.e.,
when characters are continually transmitted.
If the number of command characters is A, the number of response characters is B, the baud rate is
38,400 bps, the data length is 8 bits, the parity is even, and there is 1stop bit, the following formula can
be used.
The above formula finds the time when processing is started (command transmitted) with the Tag inside the communications
area of the CF Reader/Writer. The time depends on the communications mode and the Tag status.
When write protection is used +2.9 ms
When the start address is not a multiple of 4 +2.9 ms
When the end address (start a number of addresses) is not a multiple of 4 +2.9 ms
TAT = Command transmission time + Communications time + Response transmission time
Transmission time =
Bits per character
Baud rate (bps)
TAT =
11
×
(A + B)
38400
+ communications time