Transfer Time - Mitsubishi Electric MELSEC iQ-F Series FX5 User Manual

2.5

Transfer Time

Link time
■Calculation method
Calculate the minimum processing time of the SLMP communication by the following calculation formula.
However, the processing time may become longer depending on the load of the network (how much a line is crowded),
window size of each connecting device, number of connections to be used simultaneously, and system configuration. As a
guideline, recognize the value calculated by the following calculation formula as the processing time when a communication is
executed by only one connection.
• Minimum processing time of the SLMP communication (for batch read or batch write)
Tfs = Ke + (Kdt  Df) + Scr  Number of scans required for processing + ACK processing time of external equipment
Tfs: Time from when the request data of a personal computer is received until the CPU module completes the processing
*1
(Unit: ms)
Ke, Kdt: Constant (Refer to the following table.)
Df: Number of words of the request data + Number of words of the response data (application data part)
Scr: Scan time
*1 The following shows the timing from when the request data of a personal computer is received until the CPU module completes the
processing.
External device
(personal computer)
Command
message
Step 0
Scan time of the
CPU module
Communication
description
Batch read
Batch write
Ex.
[Calculation example 1]
Time from when the request data of a personal computer is received until the processing is completed, when a TCP/IP
communication is executed between personal computers and 32 points data read from the data register (D) of own station by
the SLMP communication in binary code (Unit: ms)
The scan time of the mounted station is 40 ms.
Tfs = 1 + (0.001  32)+40  1 + ACK processing time of external equipment
[Calculation example 2]
Time from when the request data of a personal computer is received until the processing is completed, when a TCP/IP
communication is executed between personal computers and 32 points data written to the data register (D) of own station by
the SLMP communication in binary code (Unit: ms)
The scan time of the mounted station is 40 ms.
Tfs = 1 + (0.001  32)+40  1 + ACK processing time of external equipment
2 SLMP DATA COMMUNICATION
14
2.5 Transfer Time
Response
ACK (only
message
for TCP)
Tfs
TCP/IP communication
Ke Kdt
1 0.001
1 0.001
ACK (only
for TCP)
END Step 0
UDP/IP communication
Ke
1
1
END
Kdt
0.001
0.001