Cables
GFK-0356Q
Chapter 10 Cables
10-25
10
Expansion Port Pin Assignments
The following table lists the expansion port pin assignments you will need when building remote
cables. All connections between cables are point-to point, that is, pin 2 of one end to pin 2 of the
opposite end, pin 3 to pin 3, etc.
Table 10-2. Expansion Port Pin Assignments
Pin Number
Signal Name
Function
16
DIODT
I/O Serial Data Positive
17
DIODT/
I/O Serial Data Negative
24
DIOCLK
I/O Serial Clock Positive
25
DIOCLK/
I/O Serial Clock Negative
20
DRSEL
Remote Select Positive
21
DRSEL/
Remote Select Negative
12
DRPERR
Parity Error Positive
13
DRPERR/
Parity Error Negative
8
DRMRUN
Remote Run Positive
9
DRMRUN/
Remote Run Negative
2
DFRAME
Cycle Frame Positive
3
DFRAME/
Cycle Frame Negative
1
FGND
Frame Ground for Cable Shield
7
0V
Logic Ground
I/O Expansion Bus Termination
When two or more baseplates are cabled together in an expansion system, the I/O expansion bus
must be properly terminated. The I/O bus
must be terminated
at the last baseplate in an expansion
system. Each signal pair is terminated with 120 ohm, 1/4 watt resistors wired between the
appropriate pins, as follows (see the above table, also):
pins
16 – 17; 24 – 25; 20 – 21; 12 – 13; 8 – 9; 2 – 3
The I/O bus termination can be done one of the following ways:
Ŷ
By installing an
I/O Bus Terminator Plug,
catalog number IC693ACC307, on the last
expansion baseplate (local expansion baseplate or remote baseplate) in the system. The
Terminator Plug has a resistor pack physically mounted inside of a connector. The I/O Bus
Terminator Plug is shipped with each baseplate; only the last baseplate in the expansion chain
can have the I/O Bus Terminator Plug installed. Unused I/O Bus Terminator Plugs can be
discarded or saved as spares.
Ŷ
If an expansion system has only one expansion baseplate, the I/O bus can be terminated by
installing as the last cable, the 50 foot (15 meter) I/O Expansion cable, catalog number
IC693CBL302 or IC693CBL314. These cables have the termination resistors installed in the
end that connects to the expansion baseplate connector.
Ŷ
You can also build a custom cable with termination resistors wired to the appropriate pins for
installation at the end of the bus.
