Andrey Posted November 15, 2015 Report Share Posted November 15, 2015 Controller^ V570-57-T20B COM 2 configured as RS485/ Pin 1 is the "A+" signal. Pin 6 is the "B-" signal. What has "signal ground" pin? 2 or 5 ? Quote Link to comment Share on other sites More sharing options...
cantcliff Posted November 16, 2015 Report Share Posted November 16, 2015 RS-485 is a two wire differential protocol for the Vision series. There is no signal ground. Quote Link to comment Share on other sites More sharing options...
Andrey Posted November 16, 2015 Author Report Share Posted November 16, 2015 https://en.wikipedia.org/wiki/RS-485 Please read the section named as "connectors". IMHO: network without SG (signal ground) worked very bad. Quote Link to comment Share on other sites More sharing options...
AlexUT Posted November 16, 2015 Report Share Posted November 16, 2015 Hi Andrey, Following is a link to Unitronics document http://www.unitronics.com/docs/technical-library/unitronics-devices-and-rs485.pdf "Unitronics Devices and RS485". It explains in details RS485 wiring. I hope this helps. Quote Link to comment Share on other sites More sharing options...
cantcliff Posted November 16, 2015 Report Share Posted November 16, 2015 https://en.wikipedia.org/wiki/RS-485 Please read the section named as "connectors". IMHO: network without SG (signal ground) worked very bad. Andrey, Typically yes, if you use 0v as your reference. RS-485 two wire uses the voltage differential between A+ and B- as it's reference on a twisted pair wire. The biggest advantage is both wires would be prone to the noise. So if A+ is offset, B- is also offset by an identical amount and the differential is maintained. There are also a 3 wire spec, and a 4 wire spec (4 wire is used for full duplex communication). As always, you should still use grounded cable with the ground connection on one end to improve performance and minimize noise. Quote Link to comment Share on other sites More sharing options...
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