Hitachi S10mini User Manual page 176

5 USER GUIDE
(2) For FL-net protocol version Ver. 2.00 (Model: LQE502)
The method of calculating the communication performance of the FL-NET module is shown
below. However, the method varies depending on the destination of the connection and
number of words. Accordingly, the worst case scenario is shown below on the supposition of
communication performance between FL-NET modules.
The meanings of symbols used in the expression are shown below.
S: Number of transmitted words of the self-node (words)
R: Number of received words sent from the previous node to the self-node (words)
F: Quotient resulting from dividing (S - 1) by 512
(Example: F = 0 when S = 512, F = 1 when S = 513)
Fn: F of each node. n is the node number.
RCT: Refresh cycle time (ms)
SCT: Sequence cycle time (ms)
MS: Transmitted message word count (bytes)
MR: Received message word count (bytes)
MFT: Minimum frame interval (ms)
W: Total number of transmitted words of all nodes (words)
n: Number of connected nodes
Token hold time (ms): Token holding time of the self-node.
Token hold time = 2.7 + 0.0034 × S + 0.0032 × R + 2.74 × F + MFT ...............[When 0 ≤ MFT < 2]
Token hold time = 2.7 + 0.0034 × S + 0.0032 × (0.87 + MFT) × F + MFT.......[When MFT ≥ 2]
Refresh cycle time (ms): Sum of the token hold time valves of all the nodes.
Refresh cycle time = 2.7 × n + 0.0066 × W + 2.47 × (F1 + F2 + F3 ...... + Fn)
Refresh cycle time = 2.7 × n + 0.0066 × W + (0.87 + MFT) × (F1 + F2 + F3 ...... + Fn)
Cyclic transfer throughput (ms)
Time from setting data in the memory of the transmitting side CPU to calculation by the
ladder program of the receiving side CPU.
Cyclic transfer throughput = RCT + SCT ...........................................................[For ladder processing]
Cyclic transfer throughput = RCT.......................................................................[For C mode processing]
...............[When 0 ≤ MFT < 2]
...............[When MFT ≥ 2]
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