7-79
Calculation example 3
When all but one station have been added to a 16-unit link, the largest station number is 16, relays and
registers have been allocated evenly, and the scan time for each PLC is 5 ms.
Ttx = 0.096 Each Ts = 5 + 6.82 = 11.82 ms
Tlt = 0.096 x (13 + 2 x 15) ≒ 4.13 ms
Tlk = 0.96 + 400 + 0.67 + 5 ≒407 ms
Note: The default value for the addition waiting time is 400 ms.
Given the above conditions, the maximum value for the transmission time (T) of one cycle will be:
T max. = 11.82 x 15 + 4.13 + 5 + 407 = 593.43 ms
Calculation example 4
When all stations have been added to an 8-unit link, the largest station number is 8, relays and register
have been evenly allocated, and the scan time for each PLC is 5 ms.
Ttx = 0.096 Each Pcm = 23 + (8 + 16) x 4 = 119 bytes
Tpc = Ttx x Pcm = 0.096 x 119 ≒ 11.43 ms
Each Ts = 5 + 11.43 = 16.43 ms Tlt = 0.096 x (13 + 2 x 8) ≒ 2.79 ms
Given the above conditions, the maximum value for the transmission time (T) of one cycle will be:
T max. = 16.43 x 8 + 2.79 + 5 = 139.23 ms
Calculation example 5
When all stations have been added to a 2-unit link, the largest station number is 2, relays and registers
have been evenly allocated, and the scan time for each PLC is 5 ms.
Ttx = 0.096 Each Pcm = 23 + (32 + 64) x 4 = 407 bytes
Tpc = Ttx x Pcm = 0.096 x 407 ≒ 39.072 ms
Each Ts = 5 + 39.072 = 44.072 ms Tlt = 0.096 x (13 + 2 x 2) ≒ 1.632 ms
Given the above conditions, the maximum value for the transmission time (T) of one cycle will be:
T max. = 44.072 x 2 + 1.632 + 5 = 94.776 ms
Calculation example 6
When all stations have been added to a 2-unit link, the largest station number is 2, 32 relays and 2
register words have been evenly allocated, and the scan time for each PLC is 1 ms.
Ttx = 0.096 Each Pcm = 23 + (1 + 1) x 4 = 31 bytes
Tpc = Ttx x Pcm = 0.096 x 31 ≒ 2.976 ms
Each Ts = 1 + 2.976 = 3.976 ms Tlt = 0.096 x (13 + 2 x 2) ≒ 1.632 ms
Given the above conditions, the maximum value for the transmission time (T) of one cycle will be:
T max. = 3.976 x 2 + 1.632 + 1 = 10.584 ms
Note:
• In the description, “stations that have been added” refers to stations which are connected between
station no. 1 and the largest station number and for which the power supply has been turned on.
• Comparing examples 2 and 3, the transmission cycle time is longer if there is one station that has not
been added to the link. As a result the PC(PLC) link response time is longer.
• The SYS1 instruction can be used to minimize thte transmission cycle time even if there are one or
more stations that have not been added to the link.
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