Processing Time Of Communications Using Modbus/Tcp; Calculation Formula - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Processing time of communications using MODBUS/TCP

The following shows the time required by the Ethernet-equipped module when it receives a request message from the
MODBUS/TCP master device, completes the processing, and sends a response message.

■Calculation formula

Tsl = Ks1 + (Ks2  n1) + (St  n2) [ms]
Variable Meaning
Tsl Request message processing time (performance of the automatic response
function) (unit: ms)
Ks1 Internal processing time of the automatic response function (unit: ms)
Ks2 Communication time between the Ethernet-equipped module and CPU module
(unit: ms)
St Own station scan time (unit: ms)
n1 Function code for the processing target and setting details of the memory
assignment
n2 Function code for the processing target and setting details of the memory
assignment
Processing time, constant

Fixed to 2.5ms
Fixed to 4.5ms

Function code CPU module device
assignment
01 1
02 1
03 1
04 1
05 1
06 1
15 1
16 1
20 1
21 1
22 2
23 2
Function code CPU module device
assignment
Normal Worst
case
01 1 2
02 1 2
03 1 2
04 1 2
05 1 2
06 1 2
15 1 2
16 1 2
20 1 2
21 1 2
22 2 4
23 2 4
Appendix 7 Processing Time
Buffer memory
assignment
0
0
0
0
0
0
0
0
0
0
0
0
Buffer memory A
assignment
0
0
0
0
0
0
0
0
0
0
0
0
APPX
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