john.ward Posted October 12, 2013 Share Posted October 12, 2013 I have a PC with two built in RS422/485 Ports and am curious if there is a way to use them versus USB to RS485 adapters. I realize that I would probably have to build custom cables to connect them to my LOR network. Any feedback would be greatly appreciated. JW Link to comment Share on other sites More sharing options...
k6ccc Posted October 12, 2013 Share Posted October 12, 2013 Can I assume these are either industrial computers or you added a card to get them? Off hand, they would likely work. To your computer, the RS485 adapter just looks like a serial port. Yes, you would likely have to build your own cable. Link to comment Share on other sites More sharing options...
Don Posted October 12, 2013 Share Posted October 12, 2013 You could always purchase one of the 'original' style LOR Adapters... Here it is in the store. Link to comment Share on other sites More sharing options...
a31ford Posted October 13, 2013 Share Posted October 13, 2013 The LOR cable is 4 & 5 are "A" and "B" on the 485 network, and 3 is LOR power Positive, 6 is LOR power Ground, 1,2, 7, & 8 are not used. (CAT 5 connectors). For you the A and B are all you need (and a pair of 120 ohm resistors) (computer, and LAST controller on the network) MUST be daisy-chain type network NO star or "y" connections permitted. what are your 485 serial connectors on the computer , DB-9, DB-25, or CAT5 ???? Greg 1 Link to comment Share on other sites More sharing options...
john.ward Posted October 15, 2013 Author Share Posted October 15, 2013 It is an jetway itx mb based PC. It may be an industrial board. The board has one db-9 and one mb header port and a daughter card with 2 db-9 and 2 mb style headers. The serial ports are configurable to be rs232, rs422 or rs485. Link to comment Share on other sites More sharing options...
a31ford Posted October 19, 2013 Share Posted October 19, 2013 (edited) I sure hope you have the pin-out diagrams for the ports, there are some differences in what type of 485 pinouts exist. You will need to tie TX+ and RX+ together, and TX- and RX- together as a separate set, this will give you "A" and "B" respectively (or the opposite), technically TX+ should be "A" but I have seen other configurations. LOR positive (pin 3), and ground (pin 6) (in the CAT5 cable) are for LOR's own internal use (to power motion sensors, directors, and such) and are NOT used in the PC connection. You also might need to tie the other 4 pins used in full duplex 485 into "loopback" this should cause the "A" and "B" pair to function as a 2 wire system. I can't remember the other four pins names at the moment, will dig some old books and post them when I find my serial pinout book. Greg Edited October 19, 2013 by a31ford Link to comment Share on other sites More sharing options...
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