Appendix; Appendix 1 Calculating The Setting Values Of The Data Link Instructions (Control Data); Appendix 1.1 Calculation Formulas - Mitsubishi Electric Melsec Q Series User Manual

APPENDIX

APPENDIX

Appendix 1 Calculating the Setting Values of the Data Link Instructions (Control Data)

This section explains how to determine values set to control data for the data link
instructions (arrival monitoring time and the number of resends) and the processing
time of the instructions.
The arrival monitoring time refers to monitoring time after the Ethernet module sends a
request by the data link instruction until the instruction processing is ended.
When the processing is not ended, the instruction is resent by the number of resends.
The processing time described in this section depends on the network load ratio (line
congestion) and system configuration. When applying the value to the system, make
sure that it will not cause a problem in control.

Appendix 1.1 Calculation formulas

(1) Arrival monitoring time
App - 1
The formula is shown using the following system configuration example.
(Communication request source station)
Arrival monitoring time > St × 2 + Dt + Rt
St: Sequence scan time of the CPU module on the communication request
source station
Dt: Communication processing time between the Ethernet modules on the
communication request source station and on the communication request
destination station
Rt: Response time of the CPU module on the communication request destination
station
(a) Sequence scan time of the CPU module on the communication request
source station (St)
The sequence scan time can be checked by Current scan time (SD520,
SD521).
(b) Communication processing time between the Ethernet modules on the
communication request source station and on the communication request
destination station (Dt)
Use the processing time of the dedicated instructions described in the User's
Manual (Basic).
(Communication request destination station)
READ instruction
1 channel used
MELSEC-Q/L
A
App - 1