Master-slave 2-wire communication with Temperature Controller via Modbus RTU (USB-485) protocol.

[antonio.matar]

I am also using the USB-485/1 adapter from NI.  It has a DB9 (male) connector which I plugged to a DB9 (female) externally do the wiring related to the 2-wire communications (pin4-8 and pin5-9).  I didn't connected pin 1 (GND) to anywhere else though.

I tryed what Closing the VISA port as you recommended (just like in the example), but continue having the same old error from previous posts....damn!

[antonio.matar]

Hi guys, it works now!

Here's what I made

HW Related:

I re-made the cable which communicates the USB-485 with my TC's.

SW Related:

I pulled out another PIN out of "MB Serial Init.vi" to manually control the "Stop Bit" variable

I set the same timout time in my TC's and in LV.  In the "MB Serial Init.vi" there's a default time of 100000ms, but the max. timeout in my TC's was set to 250ms

Now I am using the following parameters:  RTU, 8,n,2, timeout=250, flow control=none

Thanx again for all your comments, I  hope these posts are useful to someone....i think it was the cable all the time:S