NOTE: THESE ARE GENERAL TIPS – REFER TO THE INSTRUMENT MANUFACTURER FOR SPECIFIC RECOMMENDATIONS

For RS485 / RS422 Multidrop applications, it is essential that correct daisy-chain wiring is used.  The most common mistake in RS485 wiring is not having a true “Daisy Chain”. When instruments are mounted in cabinets it is logical to not take the daisy chain all the way to the controllers but to daisy chain the cabinets.

We recommend and can supply B&B electronics converters, specifically:

• For RS232 to RS485/RS422: Use 485OI9TB with 485 PS2 power supply. Note: the converter must be plugged directly into the RS232 port on the PC or connected using a 9-pin extension cable that has all 9 wires connected. Note that not all USB-to-serial converters work properly, especially the cheap ones!
• For USB connections we recommend USOPTL4, this is a USB-to-RS485 converter.

The B&B converters listed above support “Automatic send data control” and so work very well with SpecView.

We do not recommend using non-isolated port powered converters  or internal 485/422 cards in industrial applications.

See here for more details on RS232 / RS485 / RS422

See here for help troubleshooting comms.

 

(C) 2025  SpecView Inc & SpecView Ltd.  Page Updated: 07 January 2025