Wavelength Electronics LFI-3751, User Manual

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1
25
25
1
72
Chapter 3 - Rear Panel Operation
Connector Pinouts
2. RS-232 Connectors
These connectors meet the RS-232C standard for wiring. See Chapter 4 for
detailed RS-232 commands. Some computers may require a null modem
for proper operation. Check your computer’s RS-232 port for proper wiring
before connecting to the instrument.
RS-232 Output
The RS-232 output connects to another Wavelength Electronics
instrument with addressable RS-232 interface. The
RS-232 OUTPUT
always connects to the other instrument’s RS-232 INPUT connector.
Up to 99 instruments can be daisy chained together and controlled from
one RS-232 port on a computer.
RS-232 Input
The RS-232 input can be connected to any RS-232 port on a computer.
The proper configuration of the computer’s RS-232 port is 8, N, 1
(8 bits, no parity, 1 stop bit).
3. Controlling Multiple Instruments via RS-232
Bottom
View
GND
V
out
V
s
8
240 k
Ω
(for either
package)
GND
V
out
V
s
to pin 8
to pin 5
to pin 4
TO-92
(plastic package)
1
9
4
5
LM35
TO-46
(metal can package)
Bottom View
Example LM35 Wiring
DB-9
or DB-25
To Host
Computer
115V
!
115V
!
115V
!
115V
!
RS-232 Connector
from host computer
Unit 1 Unit 2 Unit 3 Unit 99
RS-232 Output
(25 pin male D-sub plug)
RS-232 Input
(25 pin female D-sub receptacle)
2
3
7
Peripheral Transmit
Peripheral Receive
Signal Ground
2
3
7
5, 6, 8, & 20 shorted Instrument Receive (In)
Instrument Transmit (Out)
Signal Ground