Install / Wire
535-PROF User's Manual
Chapter 3
19
•
Mechanical relay or solid state relay modules must be installed in
output sockets 1 and 2.
•
When using velocity control (no slidewire feedback), there are no con-
nections at terminals 10, 11 and 12.
•
Use of the slidewire feedback is optional
Serial Communications
A twisted shielded pair of wires should be used to interconnect the host and
field units. Belden #9414 foil shield or #8441 braid shield 22-gauge wire are
acceptable for most applications. The foil shielded wire has superior noise
rejection characteristics. The braid shielded wire has more flexibility. The
maximum recommended length of the RS 485 line is 4000 feet. Termination
resistors are required at the host and the last device on the line. Some RS 485
cards/converters already have a terminating resistor. We recommend using
RS-232/RS-485 converter (Product #500-485). The communication protocol is
asynchronous bidirectional half-duplex, hence the leads are labelled
Comm +
and
Comm –.
PC
or other host
535
Terminals
RS-485
port
Twisted, shielded
To "Comm -" terminal of
next Powers device
To "Comm +" terminal of
next device
Comm +
Comm -
Use a 60 to 100 Ohm terminating resistor
connected to the two data terminals of
the final Powers device on the line.
CAUTION
The shield needs to be connected continuously
but only tied to one ground at the host.
Failure to follow these proper wiring practices
could result in transmission errors and other
communications problems.
26
27
Figure 3.16
Serial Communications Terminals
