Brooks MFC5850s and NI PCI 8431/2 connection

[Regmars]

Hello everybody,

I try to connect two MFC5850s from Brooks with a NI PCI8431/2 RS-485 card.

Those devices are in two wires mode (without RTS or CTS control).

On the RS-485 side, I have connected RX+ & TX+ together and RX- & TX-.

The + common wire is plug on the 'Common A(+)' pin and the - common wire is plug on the 'Common B(-)' on each MFCs.

I have verified the RS-485 parameters (Baud rate, stop bit, parity...) all is ok.

I have configured the COM port in "2-wires mode auto".

I have try to establish communication with Smart DDE from Brooks, without results.

I cannot communicate with the MFCs.

Is somebody have an idea to help me ?

Thank you very much for your help.

[Regmars]

I reply myself,

Use the NI-SERIAL 3.6 driver and never the 3.5 version !

It correct a bug that don't permit to change the wiring configuration of the RS-485 card (that do be set on 2-wires auto mode).

[JasonSmith]

NI-Serial 3.6 did correct a bug where the default wire-mode from Measurement & Automation Explorer would not be used. It was still possible to change the wire mode if it were changed programmatically through your application. I agree that upgrading the driver is the best solution for this problem.

-Jason S.