5 Creating Project Files—Modbus Master to Devices
register 40001, etc. Be sure that the registers you specified are not being used by other devices.
3.Select Save to save the information to the project file, and then select Ok or press Esc to exit the device diagnostic registers screen. If at any time you want to return to the last saved version of the device diagnostics registers, select Revert with- out saving any changes.
ing to the appropriate register. The first register con- tains the command, and the second register contains the data associated with the command. The format of the command registers for each device are described in Appendix E.
All the command registers are placed in contiguous locations and are assigned to each device in the order that they are listed in the device list. To indicate the location of the command registers, follow these steps:
5.11Device Command Registers
The device command registers consist of two consec- utive registers for each device entered in the device list. These registers allow the Modbus Master device to transmit commands to each of the devices by writ-
1.Select Device Command Registers from the Edit menu. The Device Command Registers screen appears:
2.Enter the starting register address in the Modbus Registers field. The DTU3005 Editor software will determine the proper number of registers for the number of devices entered in the device list and indicate the final register number. The registers used are the holding registers (40000 to 49999). Thus entering a register number of 1 will repre- sent register 40001, etc. These registers must be different from those used for device data and diagnostics. Failure to use different register addresses will cause communication errors, and may cause unexpected operation of the devices.
3.Select Save to save the information to the project file, and then select Ok or press Esc to exit the device command registers screen. If at any time you want to return to the last saved version of the device diagnostics register, select Revert without saving any changes.
5.12Saving the Project File
Now you have completed configuring the DTU3005 for Modbus Master to Devices communications. Select Save from the Project menu and press Enter, or press F10 to save the project file to disk. The next step is to transfer the project to the DTU3005 unit. This topic is covered in Chapter 7.
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