Campbell Scientific SC32A Optically Isolated RS232 Interface - Manual (Page 3)

1
SC32A OPTICALLY ISOLATED RS232 INTERFACE
1. FUNCTION
The SC32A interfaces an RS232 peripheral,
commonly a computer or printer, to the Serial
I/O of a CSI datalogger. The SC32A replaces
the SC32. Functions include:
1. Converting datalogger logic levels to RS232
logic levels.
2. Optically isolating the datalogger and the
RS232 peripheral. Optical isolation
separates the SC32A into a datalogger
section and an RS232 section. Signals
entering from either side are electrically
independent, protecting against ground
loops, normal static discharge, and noise.
3. Passing data when pins 5 or 6 of the
datalogger I/O are high and the on-board
jumper is removed (see SC32A Component
Location Diagram, Figure 5.1).
4. Passing data when pin 5 is high and pin 6 is
low when the jumper is in place.
SC32As with serial numbers less than 1500
were shipped with the jumper in a blocking
position (two posts connected). Serial numbers
1500 and greater are shipped with the jumper
on one post only, in the passing position.
When used with a CR10 Measurement and
Control Module, the correct SC32A jumper
position depends on the application. For all
other CSI dataloggers, the jumper has little
effect and could be removed (Section 5).
2. SPECIFICATIONS
Operating temperature: -25 to +50
°
C (typical)
Power: Powered by host devices, see
"Operation" section
Ports: 25 pin (sockets) configured as DCE. 9
pin (pins) connect to CSI datalogger through
SC12 Two Peripheral Cable (included)
Size: 2.25 x 1.0 x 3.5 inches, 0.25 lbs.
3. CONNECTOR DESCRIPTIONS
3.1 25 PIN
The SC32A 25 pin female port is configured as
Data Communications Equipment (DCE) for
direct cable connection to Data Terminal
Equipment (DTE). Most terminals, computers,
and printers are configured as DTE. For
connection to DCE devices such as modems
and some computers, a null modem is required.
A null modem configuration is given under
"Special Cases", Section 5.3.
3.2 9 PIN
The SC32A 9 pin male port connects to the
datalogger through the SC12 Two Peripheral
Cable supplied with the SC32A. Pin
descriptions and direction (Input/Output) are
given in Table 3.1.
TABLE 3.1 SC32A CONNECTOR DESCRIPTIONS
25 PIN FEMALE CONNECTOR 9 PIN MALE CONNECTOR
PIN # I/O DESCRIPTION PIN # I/O DESCRIPTION
1 GROUND 1 IN +5V
2 IN TX 2 GROUND
3 OUT RX 3 OUT RING
4 IN RTS (POWER) 4 OUT RX
5 OUT CTS 5 IN ME
6 OUT DSR 6 IN PE (CR10 SDE)
7 GROUND 9 IN TX
8 OUT DCD
20 IN DTR (POWER)