QUANTUM™ HD COMPRESSOR CONTROL PANEL
COMMUNICATIONS SETUP
090.040-CS (JAN 14)
Page 11
SECTION 2
SERIAL COMMUNICATIONS
• Enabled
SERIAL COMMUNICATIONS DESCRIPTION
RS-422/RS-485 DESCRIPTION
When serial communications started moving into
the industrial environment, it was quickly noted that
because of the high electrical noise potential from
electric motors, valves, solenoids, fluorescent light-
ing, etc., that the noise immunity characteristics of
RS-232 protocol was grossly lacking. Additionally, the
distances between the communicating equipment on
the factory floor was much greater than that within
the typical office environment. For these reasons,
RS-422 and RS-485 was developed.
• RS-422 is a full duplex communications hardware
protocol. This means that it data can be sent and
received simultaneously. Frick
®
Controls uses a
4-wire system for RS-422 (two transmit wires
and two receive wires). Advantages of RS-422
over RS-232 is that up to 30 Quantum™ con-
trollers may be simultaneously connected using
a daisy-chain wiring scheme (to be explained
later), and that the distances involved can be
much greater (typically up to 2000 ft. for the to-
tal cable run), much greater noise immunity than
RS-232.
• RS-485 is a half duplex bus. This means that it
can only send data, or receive data at any given
time. It cannot do both at the same time. Frick
®
Controls uses a 2-wire system for RS-485 one
positive transmit/receive wire and one negative
transmit/receive wire). Up to 30 Quantum™ con-
trollers may be simultaneously connected up to
a total distance of 2000 ft. using a daisy-chain
wiring scheme (to be explained later). One ad-
vantage to using RS-485 as opposed to RS-422
is that only a single twisted pair cable need to
be run to all devices (while RS-422 requires a
double twisted pair cable), much greater noise
immunity than RS-232.
SERIAL COMMUNICATIONS SETUP
After the serial communications wiring has been connected,
and jumpers correctly set, the HD software needs to be setup
to match that of the device(s) that it is to communicate with.
The following page is where this information can be found:
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