4P642495-1A
–
2022.02
Page
14
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52
2.2.2 Character format
Each byte of a message is sent as character data as follows.
A character consists of start bit (0), 8 bits data, parity bit and stop bit (1). One character size is always 11 bits
and stop bit 1 or 2 is selected by parity bit.
[Non Parity]
0 (LSB)
1
2
3
4
5
6
7
8
9
10 (MSB)
Start bit
Data
Stop bit 1
Stop bit 2
[Parity]
0 (LSB)
1
2
3
4
5
6
7
8
9
10 (MSB)
Start bit
Data
Parity bit
(Odd or
Even)
Stop bit 2
2.2.3 Silent internal time
Every frame needs to have silent interval time (T1-T2-T3-T4) before and after. The silent interval time is
depending on communication speed.
Baud Rate(bps)
9600
19200
Silent Interval Time(ms)
(T1-T2-T3-T4)
5
2,5
2.2.5 Response time
This
Modbus Interface DIII
responds a message after response time(t1) when this
Modbus Interface DIII
receives a query message. The response time(t1) of this
adaptor is “Silent Interval Time(T1
-T2-T3-
T4) + 20ms”.
Modbus master needs to wait to send next query message for time interval(t2) when the modbus master
receives a response from the
Modbus Interface DIII
. The time interval(t2) should be more than “Silent Interval
Time(T1-T2-T3-
T4) + 20ms”.
Modbus master
Modbus Interface DIII
Query message
Response
Query message
t1
t2
t1 = (T1-T2-T3-T4) + 20 (ms)
t2 >= (T1-T2-T3-T4) + 20 (ms)
