help first time modbus with inverter toshiba

[gekaras]

Good afternoon,

I am a wood working machine manufacturer from greece.I work many years with unitronics plc and i am very satisfied.

I have start 1 new project that i want to use V280 or V290, with 3 inverter for speed control.

The inverter is toshiba vf nc3 and i will use 3 of them.

I dont want to use the contact option on the inverter and i want to use modbus rs485 protocol but i have never worked at the past with.

Does anyone know the correct steps how to start or also an example?

is it possible to work with hex for read and write?

[Joe Tauser]

1. Read the Visilogic Help on both Modbus and RS485 to learn what will be needed to establish communication with the drives.

2. Look at Help->Examples->Version 900->Project Examples->Communications->MODBUS->V120_Modbus_Master.vlp.

3. Get the Modbus table for your drive. Modify the example PLC program to match the hardware you are using and add some screens that will allow you to easily trigger Modbus reads and writes; you'll need to establish successful communication with one drive before you can go any further.

Hex is not a problem.

Let us know when you've gotten the PLC to talk to one drive, or if you have programming questions make sure you post what code you've written. It is extremely difficult to answer code-related questions without the code to look at.

Joe T.

[Walkerok]

Just a note that may help people thinking about hex and decimal. When you take either form down to the bit level they are exactly the same so even if hex were not avaialble you can represent everything in decimal or visa versa.

For example hex 13A = 100111010 (binary) = 330 (decimal)

Keith