User`s manual

5
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
Table of Contents
9. Slave Specification 84
9.1 MODBUS Slave Command Code List........................................................................................... 84
9.2 MODBUS device address allocation ............................................................................................. 85
9.3 MODBUS device address allocation (Default Values) .................................................................. 85
9.4 User defined MODBUS Device Address Assignment ................................................................... 87
9.4.1 Format of the user defined device allocation................................................................................. 88
9.4.2 Example of user defined device allocation .................................................................................... 90
9.5 Communication Event log ............................................................................................................. 94
9.5.1 Communications event log ............................................................................................................ 94
9.5.2 Communication event log timing and storage format .................................................................... 95
10. Creating Programs 97
10.1 Checking Contents of Related Devices....................................................................................... 97
10.2 Creating Programs for the Master Station................................................................................... 97
10.3 Creating Programs for the Slave Station..................................................................................... 98
10.4 Cautions on Program Creation.................................................................................................... 99
11. Practical Program Examples 100
11.1 Setting Program for Master Station........................................................................................... 100
11.2 Setting Program for Slave Station............................................................................................. 102
12. Troubleshooting 103
12.1 Checking the FX3U PLC Version Applicability.......................................................................... 103
12.2 Checking the Communication Status Based on LED Indication ............................................... 103
12.3 Checking the Installation and Wiring......................................................................................... 103
12.4 Checking the Communication Settings and Sequence Program .............................................. 103
12.5 Checking Setting Contents and Errors...................................................................................... 104
12.6 MODBUS Error Code List ......................................................................................................... 106
Warranty................................................................................................................................. 111
Revised History ..................................................................................................................... 112