Timeout error arises when i comunicate using Modbus

[Arvind_Soliton]

I tried to communicate with the thermal controller using modbus. But i get timeout error.

How can i overcome this?

[Wayne.C]

Is this serial modbus or ethernet?  If it is serial, ASCII or RTU.

[Arvind_Soliton]

The communication is through Serial, mode is RTU.

Message Edited by Arvindti on 01-09-2008 12:17 AM

[Wayne.C]

Suggest that you start by verifing your com port settings.  I personally suggest that these all be set in your vi.

Spec calls out for 8 data bits for RTU mode.  No other choices here.

Partiy can be even, odd or none.

The number of stop bits depends on the parity setting.  If you are using even or odd parity, then 1 stop bit.  If you are using no parity, then 2 stop bits.  This is an often overlooked setting and what I usually mess up.  :

Make sure that the controller communication settings match those of your vi.  BAUD rate, parity and especially the address of the controller.

The next step would be to start looking at your connections to the controller.