Campbell SC32B Instruction Manual - 3. Connector Descriptions
SC32B Optically Isolated RS-232 Interface
2
3. Connector Descriptions
TABLE 3-1. SC32B Connector Descriptions
RS-232
9 Pin Female Connector
CS I/O
9 Pin Male Connector
Pin #
I/O
Description
Pin #
I/O
Description
1
Out
DCD
1
In
+5 V
2
Out
RXD
2
Ground
3
In
TXD
3
Out
Ring
4
In
DTR
4
Out
RX
5
Ground
5
In
ME
6
Out
DSR
6
In
PE (SDE)
7
In
RTS
7
No Connection
8
Out
CTS
8
No Connection
9
No Connection
9
In
TX
3.1 RS-232
The DB9 RS-232 port is configured as Data Communications Equipment
(DCE) for direct cable connection to Data Terminal Equipment (DTE). Most
computers are configured as DTE. For connection to DCE devices such as
modems, the SC932 or SC932A should be used in place of the SC32B.
3.2 9 Pin
The CS I/O port connects to the datalogger through the SC12 Two Peripheral
Cable supplied with the SC32B. Pin descriptions and direction (Input/Output)
are given in Table 3-1.
4. Operation
Power for the SC32B datalogger section comes from the 5 V supply on pin 1 of
the datalogger CS I/O. Communication logic levels to and from the datalogger
are referenced to this voltage, ranging from 0 to slightly less than 5 V.
Power for the RS-232 section is isolated from the datalogger 5 V supply via a
transformer/isolator. An on-board DC to DC converter supplies the negative
voltage required for RS-232 signals.
When the SC32B first receives a character from the RS-232 peripheral (pin 3),
5 V is applied to the datalogger Ring line (pin 3) until the datalogger Modem
Enable (ME) goes high, putting the datalogger into the Telecommunications
Mode.