The "Init" jumper on the server module should only be used when advised by tech support. Installing this
jumper prior to power-up causes the server to go into firmware update mode.
A.4 Babel Buster SP DB-9 Connector & DIP Switch
Pin connections are shown below. RS-485 (EIA-485) is by definition 2-wire. Any reference to 4-wire
RS-485 is really EIA-422. Babel Buster SP supports EIA-422, but also automatically supports EIA-485 with
a simple wiring configuration. Simply connect all the pluses together, and all the minuses together.
Connect RXD+ to TXD+ on Babel Buster SP, and that one connection to + on your Modbus device. Do the
same with the minus side. Then set the DIP switches for EIA-485 half duplex, termination ON. Although
called "2-wire" you really need 3 conductors, 2 wires for and - with a third conductor for
ground/common.
If your Modbus device has its RS-485 terminal marked A and B, be aware that about half of the equipment
out there has A and B backwards. This is due to the fact that A and B as published by EIA-485 are the
reverse of A and B as defined by the RS-485 chip makers. Somewhere along the line they didn't compare
notes. There is no harm done in reversing the wires, it simply will not communicate. If you are having
trouble communicating, especially if the device terminals are marked A and B, try reversing them.
The above view is the male DB9 as seen looking into the Babel Buster SP. Important: This is
NOT
a
PC COM port. Study the wiring table below carefully. Also keep in mind that while Pin 1 is on the left on the
male connector, Pin 1 will be on the right looking at the female connector.
A. Hardware Details
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