page 40 008-0671-00
7.3 Communications Protocol
7.3.1 RS-232 vs. RS-485
SC Series instruments are available with either of two communications protocols, RS-
232 or RS-485. Only one of these can be installed at a time at the factory.
•
RS-232 provides for only one receiver and transmitter per loop, and a loop length
of no more than 50 feet.
•
RS-485 allows up to 32 devices per loop, and a loop length of no more than 4000
feet. All devices receive messages in parallel on the line, the so-called “multi-
drop” system. To avoid garbled transmissions, only one device should respond to
a particular message. Therefore, every device on the loop must have a unique
address.
If you have an instrument with more than one channel, transmission must be
addressed to the appropriate channel within the instrument.
7.3.2 Parameters
All SC instruments use no parity, 8 data bits, and 1 stop bits (“N,8,1”) for serial com-
munications. Baud rates available are 300, 600, 1200, 2400, 4800, 9600, 19200
and 38400. As shipped from the factory, all instruments are set at 9600 baud. The
baud rates can be selected though the front panel.
Summary of Contents for SC500
Page 8: ...page 8 008 0671 00 ...
Page 14: ...page 14 008 0671 00 ...
Page 18: ...page 18 008 0671 00 ...
Page 24: ...page 24 008 0671 00 ...
Page 38: ...page 38 008 0671 00 ...
Page 42: ...page 42 008 0671 00 ...
Page 50: ...page 50 008 0671 00 ...
Page 72: ...page 72 008 0671 00 ...
Page 82: ...page 82 008 0671 00 ...
Page 90: ...page 90 008 0671 00 ...
Page 116: ...page 116 008 0671 00 ...
Page 126: ...page 126 008 0671 00 ...