Computer Link - Mitsubishi Electric MELSEC FX Series User Manual

FX communication
2.2.3

Computer link

Calculations to determine the approximate time until communication is complete.
1 ) Programmable controller
Communication time = Total number of characters based on dedicated protocol
2 ) Computer
Communication time = Number of total characters based on dedicated protocol
Note:
*1 Please count the number of characters with reference section 7.4.1 and 7.4.2 and chapter 8.
*2 Please refer to the following expression for time calculation.
Time to send or receive one character = 1/baud rate
Example
When 1 character = 10 bits (Data length = 7, Parity bit = 1, stop bit = 1 start bit = 1),
the time is as follows.
Baud rate (bps)
300
600
1200
2400
4800
9600
19200
Note;
Please refer to following table for the relation between reading word points and communication
time.
"Message time = 0ms, Maximum scan time = 20ms, Dedicated protocol format = format 1,
Command = WR, Baud rate = 9,600 or 19,200 bps"
Reading word points
10
32
64
→
Computer
×
Time to send or receive one character (ms)
+ Programmable controller's maximum scan time (ms)
+ Message wait (ms)
→
Programmable controller
×
Time to send or receive one character (ms)
+ Programmable controller's maximum scan time (ms)
+ Message wait (ms)
(start bit(1) + Data length(7 or 8) + Parity bit(0 or 1) + Stop bit(1 or 2))
Time to send or receive one character (ms)
9,600
0.3 s
0.4 s
0.5 s
×
number of bits in character
33.34
16.67
8.34
4.17
2.08
1.04
0.52
Baud rate (bps)
19,200
0.2 s
0.3 s
0.4 s
Specifications 2
*1
*2
×
3
*1
*2
2-3
2