635-SERIES HARDWARE M ANUAL
Chapter-Page
2-31
635-DSI – BOARD INSTALLATION
If you are not installing a DSI board, then skip this section.
This section covers the 635-model board. The 600 version of this board is covered in an older manual, but
as far as mounting the board into the cabinet, the steps are the same.
PART 4.4.1 (
OPTIONAL
) PRECONFIGURING THE EOL TERMINATION JUMPERS (635-DSI)
For convenience, 120 ohm Termination Jumpers are provided on the DSI Board (factory default = OPEN).
•
OPEN = no termination resistance at the DSI BOARD.
•
TERM = 120 ohm resistance is applied at the DSI Board end.
NOTICE:
•
You must install Termination at both extreme ends of the RS-485 wire run (especially in the case of Wireless
Readers, Input Boards, clocks and LCDs).
•
Each 485 Section must be configured for termination, independently. It is possible to have a wire run where one
Section is not at the EOL (
JP
=
OPEN
POSITION
), while the other Section is at the EOL (
JP
=
TERM POSITION
).
Table 22: SET THE TERMINATION JUMPERS FOR EACH SECTION
SECTION JUMPER Setting if Section is at EOL
Setting if Section is not EOL
Section-1 JP5
“TERM” (A)
OPEN (factory default) (B)
Section-2 JP4
“TERM” (A)
OPEN (factory default) (B)
(A)
Example A: If the DSI Board is at one extreme end of the wire run, you must install a matching 120-ohm
Termination Resistor at the
other extreme end
of 485 run.
(B)
Example B: IF the DSI Section is set to OPEN, then you must install a 120-ohm Resistor at
both extreme
ends
as near to the end device as possible (120-ohm resistors are supplied with the board in a Ziploc).
Figure 21 – Examples using Termination Resistance with the 635 DSI Board:
Example A – (JPx = TERM)
the DSI Section is at
one extreme end
,
with a 120-ohm Termination Resistor installed at
other extreme end
.
Example B – (JPx = OPEN)
the DSI Section is not at either extreme end.
Therefore, a 120-ohm Termination Resistor installed at
both extreme ends
.
