3 - 48 3 - 48
MELSEC-Q
3 SPECIFICATIONS
3.5 Communication Performance
3.5.1 Link scan time
The link scan time represents a time during which the QJ71DN91 waits for responses
from all nodes after sending a polling request or bit-strobe requests.
The following shows the link scan time calculation formulas.
LS = (TIn + TOn + 0.097) + 0.222 BR + 1.0 [ms]
LS:
Link scan time [ms]
TIn:
Transmission time for data received from the n-th slave. [ms] (Refer
to (1) below.)
TOn:
Transmission time for data sent to the n-th slave. [ms] (Refer to (2)
below.)
:
Indicates that the values in the parentheses "( )" must be added up
for all of the slave nodes. (Except for reserved nodes)
BR:
Coefficient corresponding to the baud rate
500kbaud = 1, 250kbaud = 2, 125kbaud = 4
(1) How to calculate TIn
(a) When the length of the data received from the n-th slave is 8 bytes or less
TIn = BT + BTa Receive data length (bytes) [ms]
BT, BTa: Coefficient corresponding to the baud rate (See *1.)
(b) When the length of the data received from the n-th slave is 9 bytes or more
TIn = (BT + BTa 8 + 0.190) a + {BT + BTa (b + 1) + 0.450} [ms]
BT, BTa: Coefficient corresponding to the baud rate (See *1.)
a:
Result obtained by dividing the receive data length by 7
(Truncate the fractional part.)
b:
Remainder obtained by dividing the receive data length by
7
(2) How to calculate TOn
(a) When the length of the data sent to the n-th slave is 8 bytes or less
TOn = BT + BTa Transmit data length (bytes) [ms]
BT, BTa: Coefficient corresponding to the baud rate (See *1.)
(b) When the length of the data sent to the n-th slave is 9 bytes or more
TOn = (BT + BTa 8 + 0.130) c + {BT + BTa (d + 1) + 1.2} [ms]
BT, BTa: Coefficient corresponding to the baud rate (See *1.)
c:
Result obtained by dividing the transmit data length by 7
(Truncate the fractional part.)
d:
Remainder obtained by dividing the transmit data length by 7
*1 The following shows the coefficients corresponding to the baud rates.
125kbaud 250kbaud 500kbaud
BT
0.376 0.188 0.094
BTa
0.064 0.032 0.016
Содержание QJ71DN91
Страница 1: ...DeviceNet Master Slave Module User s Manual QJ71DN91 GX Configurator DN SW1D5C QDNU E ...
Страница 2: ......
Страница 233: ......