ICS Advent WDT-1002, Product Manual

Page: 17 / 34

Chapter 3: Option Selection
Manual Number: 00650-009-28 Page 3-1
Chapter 3: Option Selection
Refer to the Figure 1-1: Block Diagram and Figure 3-1: Option Selection Map, when reading this
section of the manual. Card operation is determined by jumper installation as described in the
following paragraphs.
Termination
A transmission line should be terminated at the receiving end in its characteristic impedance. When
noise is a potential problem on long lines, the terminating resistance should be divided and its center
point grounded to help reduce noise voltage pickup. Install two jumpers at the positions marked LD
for 68-ohm termination resistance on the positive and negative branches of the receiving lines.
To provide bias in RS485 mode, install two jumpers at the locations BIAS (adjacent to I/O
connector J2). This provides a balancing load between the RX+ and RX- lines.
In RS485 mode, where there are multiple terminals, only the RS485 ports at EACH END of the
network should have terminating resistors as described above. To configure this card with the load
center-tapped to ground, install the LD and LD GND jumpers and the +BIAS and -BIAS jumpers as
described above. If the card is to have an ungrounded load, do as above except do not install the
LDGND jumper.
RTS Control
Install a jumper at the location marked RTS (adjacent to transformer T1) when control of the trans-
mitter or receiver by RTS is required.
CTS Control
If your application program is not going to control CTS, then it is necessary to install a jumper at the
location marked CTS, OR to install a jumper between pins 5 and 9 of the mating half of the D
connector.
NOTE
The card will not operate without one or the other of these two jumpers intalled if the computer is
not going to control CTS.
When the jumper is installed in the mating half of the I/O connector, it provides a handy diagnostic
tool because the card will not operate unless the communication cable is properly installed.