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rs485
Posted: Wed Aug 15, 2012 6:48 pm
by charliehbeijer
I open com2 on my T7A and it seems to be transmitting differential serial on pins 1 and 6, but it never goes tristate. How do you make it go tristate on the 485 bus so that other nodes may transmit? Also, is there a copy of the db9 pinout online?
Re: rs485
Posted: Thu Aug 16, 2012 8:38 am
by mark.monroe
The pin outs are in the controller help file. If you are using a converter, then you should select a driver that is designed to work with 485, like the Allen-Bradley DH485 controller and it will have the cable pins.
http://ixtalk.beijerelectronics.com/vie ... hp?f=8&t=4
Pin outs for the TxA series of HMI's
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Re: rs485
Posted: Fri Aug 17, 2012 7:18 am
by charliehbeijer
Turns out my port selection had been changed to 422 accidentally. That explains why it was always driving the bus. I changed it back to 485 and it behaves as expected.