ASG Tech Note: Connecting and Communicating with DSA
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3. Only use a B&B Electronics 232 – 485, half-duplex, port-powered
converter.
DSA is extremely picky with communication. You will experience communication errors if you are
not using the correct connection hardware. We have found the B&B Electronics converter to be
the most reliable and have had no reported communication errors when using either of the
following converters:
1. B&B 485SD9TB: (
http://www.bb-elec.com/bb-elec/literature/485sd9tb-3803ds.pdf
)
2. B&B 485BAT3: (
http://www.bb-elec.com/bb-elec/literature/485bat3-3903ds.pdf
)
You may purchase these converters directly from B&B Electronics on their website:
(http://www.bb-elec.com/product_family.asp?FamilyId=15&TrailType=Sub&Trail=12)
Note: If you are able to connect and program the DSA using any other brand of converter, please contact us
at
so we may add it to the list.
3A. Setting up and wiring your 232-485 converter:
Note: You must use a standard 9 pin serial (232-232) cable between your computer
and the 232-485 converter. Null modem cables will not work.
B&B 485D9TB Converter:
The 485SD9TB converter is the easiest to set up. Just wire
it to the DSA and start communicating!
To wire the 485SD9TB:
-
[B] is wired to + on DSA.
-
[A] is wired to – on DSA.
-
[GRD] is wired to Ground/Shield on DSA.
B&B 485BAT3 Converter:
The 485BAT3 is a more robust converter, but requires
additional set up to work properly.
To set up the 485BAT3:
-
For runs under 300’: Make sure the ‘Battery Power’ switch is in the OFF position. Do
not put a battery in the converter.
-
Make sure the ‘ECHO’ switch is in the OFF position.
-
Make sure the ‘RS-485’ switch (above the ECHO switch) is in the RS-485 position.
To wire the 485BAT3:
-
[RD B] is wired to + on DSA.
-
[RD A] is wired to – on DSA.
-
Make a small jumper and jump [RD B] to [TD B] on the converter.
-
Make a small jumper and jump [RD A] to [TD A] on the converter.
-
[GRD] is wired to Ground/Shield on DSA.
Note about 485BAT3: For normal, short runs, external wall wart power or battery power is not necessary.
For communication runs in excess of 300’, you can use external or battery power for the converter. Also, if
you made your own 232 serial cable, not from 9-wire cable, you will need external or battery power
.
