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Ver.1.1
3.2
Time period of the case that data re-transmission of divided packet is occurred at packet
transmission mode
When packet data size is exceeding 26 bytes, it is divided into several packets that data size is 26 bytes. At
that time, each divided packet is sent defined re-transmission times. Thus, maximum data transmission
period will be (setting of REG11 register + 1) x 5 times. (REG11 register is a parameter of data
re-transmission frequency.)
It takes 3.7 ms if data transmission failure is occurred once. Therefore, total data processing time is like
below formula.
Bit length per byte
Line speed
of
the sender
A: Text data is transmitted at packet transmission mode:
Binary data is transmitted at packet transmission mode:
Trigger of the data transmission is delimiter at headerless packet transmission mode:
Trigger of the data transmission is time-out at headerless packet transmission mode: 0
B: Trigger of the data transmission is time-out at headerless packet transmission mode:
Others:
Example 1: At the line speed set to 115,200 bps and bit length per byte set to 10 bits, time period of the data
transmission failure detection is 53.1 ms if the first packet data is fail to transmit. (Size of the
message is 130 bytes. Setting of data re-transmission frequency is 10 times.)
(1
0/115,200) × 1,000 × (130 + 9 + 4) + 7.3 × (10+1) × 1 = 92.7 [ms]
Example 2: At the line speed set to 115,200 bps and bit length per byte set to 10 bits, time period of the data
transmission failure detection is 215.9 ms if the fifth packet data is fail to transmit. (Size of the
message is 130 bytes. Setting of data re-transmission frequency is 10 times.)
(1
0/115,200) × 1,000 × (130 + 9 + 4) + 7.3 × (10 + 1) × 5 = 413.9 [ms]
As shown above, the total transmission time is largely fluctuated by the condition of the data transmission.
To keep communication response well, size of the message should be less than 26 bytes.
× 1000 × (size of message in bytes + A + 4) + B + 7.3
× frequency of data transmission
In this case, if data transmission failure is occurred in any given
divided packet, following packets are not transmitted. Therefore,
total data transmission period is fluctuated.
10
Expression 3
9
12
"Value of REG26" x 10
0
2
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