The Moxa CP114EL-I serial adapter supports RS-232, RS-422 and RS-485 (both 2 and 4-wire). The connections to the board are made using a converter cable with four 9-pin male D-subminiature connectors. The converter cable is supplied with the Processor Unit.
Unless otherwise specified, this cable must be provided by the installation shipyard. If you wish to use RS-422 or RS-485 serial communication, use a cable with twisted pairs.
NoteObserve that long runs of unshielded cable will pick up noise easily. This is because the RS-232 signals are not balanced.
Maximum length for an RS-232 serial cable is typically 60 meters with 2400 bps data rate, however this depends on the cable
quality. Always check the cable manufacturers specifications for the actual "shunt capacitance". A common figure is 47.5 pF/m, which gives a maximum cable length of about 50 meters.
Even though a standard exist for RS-232 pin configuration, certain manufacturer may still choose their own connector pins
for the various signals used. In order to make the RS-232 connection to your peripheral device work properly, you must always
consult the relevant instructions provided by the device manufacturer.
Pin configuration
Moxa CP114EL-I connectors / Adapter cable |
Pin |
RS-232 |
RS-422 |
RS-485 (4-wire) |
RS-485 (2-wire) |
1 |
DCD |
TXD-(A) |
TXD-(A) |
|
2 |
RxD |
TXD+(B) |
TXD+(B) |
|
3 |
TxD |
RXD+(B) |
RXD+(B) |
Data-(B) |
4 |
DTR |
RXD-(A) |
RXD-(A) |
Data-(A) |
5 |
Ground |
Ground |
Ground |
Ground |
6 |
DSR |
- |
- |
- |
7 |
RTS |
- |
- |
- |
8 |
CTS |
- |
- |
- |
9 |
|
- |
- |
- |
Minimum cable requirements
|
• |
Conductors: 2 x 5 x 0.5 mm2 |
|
• |
Screen: Overall braided |
|
• |
Maximum outer diameter: Defined by the plugs and/or the cable gland |
If you wish to use RS-422 or RS-485 serial communication, use a cable with twisted pairs. If you need to install a very long cable, increase the cross section.