Communicaiton between Eurotherm 3208 (RS485) and computer via USB-

[wliu331]

Hi, I need connect an Eurotherm 3208 (RS485) to computer via NI USB-485 converter. What I tried (Eurotherm 3208 with RS485 and NI 485-USB): 1. Following Eurotherm manual, shorting USB-485 pin4 and pin 8 connecting to HE Rx of 3208; shorting USB-485 pin5 and pin 9 connecting to HF Tx of 3208; attach 220 ohm resistor between HE and HF; connect USB-485 pin 1 to HD Com of Eurotherm 3208, but it does not work. Measurement & Automation Explorer can write (I think to USB-485 only) but cannot read from the controller. 2. Following Eurotherm manual and [NI]: 371253e, shorting USB-485 pin4 and pin 8 connecting to HE Rx of 3208; shorting USB-485 pin5 and pin 9 connecting to HF Tx of 3208; attach 220 ohm resistor between HE and HF; shorting USB-485 pin 2 and pin 3, shorting USB-485 pin 6 and pin 7; connect USB-485 pin 1 to HD Com of Eurotherm 3208, but it does not work. Measurement & Automation Explorer can write (I think to USB-485 only) but cannot read from the controller. 3. So shall I try without the 220ohm resistor? 4. And what are the right settings in Measurement & Automation Explorer? Shall I change the default settings in Measurement & Automation Explorer? Generally, I need know what the correct connections between 3208 (3 wires) and USB-485 (9 pins) are and how to communicate between 3208 and computer. Thanks a lot.

[wliu331]

Btw, I directly connected this USB-485 converter to a femle DB-9 connector with shorting pin 2 &3, shorting pin 4 & 8, shorting pin 5 & 9 and shorting pin 6 &7. I used Measurement and Automation Explorer to test this cable. However, it also shows writing has return count but reading has error. So does it mean that this USB-485 converter malfunctions or I made some mistake? How can I check that?

Will reinstallation of driver of USB-485 converter be helpful? Is this driver downloadable?

Thx a lot.

LW

[Supertramp]

You can try with reinstalling the driver, The link for downlowding it is 

Link: http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/ssnav:drv/q/usb%20485/

Regards