Response Time Of Plc Link; Response Time Of One Transmission Cycle - Panasonic FP7 Series User Manual

6.4 Response Time of PLC Link

6.4.1 Response Time of One Transmission Cycle

The maximum value of one transmission cycle time (T) can be calculated using the following
formula.
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Calculation formula
(1) Ts (transmission time per unit)
Calculation
Ts = Scan time + Tpc (PLC link sending time)
formula
Tpc = Ttx (sending time per byte) x Pcm (PLC link sending byte size)
Ttx = 1/ (baud rate kbps × 1000) × 11 ms ... approx. 0.096 ms when 115.2 kbps
Pcm = 23 + (number of relay words + number of register words) x 4 (an ASCII code needs
multiplication by four)
(2) Tlt (link table sending time)
Calculation
Tlt = Ttx (sending time per byte) x Ltm (link table sending size)
formula
Ttx = 1/ (baud rate kbps × 1000) × 11 ms ... approx. 0.096ms when 115.2 kbps
Ltm = 13 + 2×n (n = No. of added units)
(3) Tso (master unit scan time)
To be checked using tool software.
(4) Tlk (link addition processing time)
Calculation If all units have been added, Tlk = 0
formula
Tlk = Tlc (link addition command sending time) + Twt (addition waiting time)
+ Tls (sending time for command to stop transmission if link error occurs) + Tso (master unit
scan time)
Tlc = 10 × Ttx (sending time per byte)
Ttx = 1/ (baud rate kbps × 1000) × 11 ms ... approx. 0.096 ms when 115.2 kbps
Twt = initial value 400 ms
Tls = 7 × Ttx (sending time per byte)
Ttx = 1/ (baud rate kbps × 1000) × 11 ms ... approx. 0.096ms when 115.2 kbps
Tso = master unit scan time
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Calculation example
Condition
16-unit link with all units added
1
Max. unit number = 16
WUME-FP7COM-07

6.4 Response Time of PLC Link

Calculation process
Ttx=0.096
Each Pcm=23+(4+8)×4=71 bytes
One transmission cycle
time (T)
T max.=Ts+Tlt+Tso
7.82×16+4.32+1
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