Omron V680S - Page 31

V680S Series
31
RF Tag (8k-byte Memory)
V680S-HMD6@-@@@:
V680S-D8KF6 @ (M) (Communications speed setting: High speed)
V680S-HMD6@-@@@:
V680S-D8KF6 @ (M) (Communications speed setting: Normal speed)
V680 series
RF Tag (1K-byte memory)
V680S-HMD6@-@@@:V680-D1KP@@T, V680-D1KP66MT,
V680-D1KP66T-SP, V680-D1KP58HTN
There are no differences between Communication speed:
“normal” and “high”.
RF Tag (8K-byte memory)
V680S-HMD6@-@@@: V680-D8KF6@ (M)
There are no differences between Communication speed:
“normal” and “high”.
Travel Speed Calculations
When communicating with a moving RF Tag, specify a Repeat mode for EtherNet/IP and PROFINET or an AUTO mode for Modbus TCP.
The maximum speed for communicating with the RF Tag can be calculated simply using the following formula.
Calculation Example
The following example is for reading 128 bytes with the V680S-D2KF68, and V680S-HMD66-ETN.
Query
Communications time (ms)
N: No. of bytes processed
Read T = 0.4N + 33.0
Write (with verification) T = 0.9N + 95.1
Write (without verification) T =0.5N + 65.8
Communications time [ms]
No. of bytes (byte)
450
400
350
300
250
200
150
100
50
0
0 50 100 150 200 250 300
Write
(without verification)
Write (with verification)
Read
Query
Communications time (ms)
N: No. of bytes processed
Read T = 0.5N + 36.1
Write (with verification) T = 1.0N + 93.0
Write (without verification) T = 0.5N + 65.8
Communications time [ms]
No. of bytes (byte)
450
400
350
300
250
200
150
100
50
0
0 50 100 150 200 250 300
Write
(without verification)
Write (with verification)
Read
Query
Communications time (ms)
N: No. of bytes processed
Read T = 1.0N + 20.1
Write (with verification) T = 1.8N + 45.2
Write (without verification) T = 1.5N + 41.4
Communications time [ms]
No. of bytes (byte)
400
450
350
300
250
200
150
100
50
0
0 50 100 150 200 250 300
Write (with verification)
Write (without verification)
Read
Query
Communications time (ms)
N: No. of bytes processed
Read T = 1.0N + 19.7
Write (with verification) T = 1.3N + 38.1
Write (without verification) T = 1.0N + 34.3
Communications time [ms]
No. of bytes (byte)
400
450
350
300
250
200
150
100
50
0
0 50 100 150 200 250 300
Write
(without verification)
Read
Write (with verification)
D (Distance travelled in Interrogation zone)
Maximum speed =
T (Communications time)
D (Distance travelled in Interrogation zone) is calculated from the
actual measurement or the Interrogation zone between the
Reader/Writer and RF Tag.
In order to ensure a margin, it is preferable that the communication
time is calculated at twice.
Movement direction
Interrogation zone
Y
D
X
50
100
150
200
Y
-250 -200 -150 -100 -50 0 50 100 150 200 X
170mm
From the left chart,
Distance travelled in Interrogation zone = 170 mm when Y (communications distance) is 50 mm
Communications time T = 267.8 ms (calculated from the communications time , i.e., 2 times × (0.9 × 128 bytes +18.7)
Therefore, the maximum speed of the Tag is as follows:
D (Distance travelled in Interrogation zone) 170 (mm)
Maximum speed = =
T (Communications time) 267.8 (ms)
= 38.1 m/min