Installation - 3
43
Digital I/O Connections
As shown in Table 3-3 and Figure 3-11, the FLT/INH connector can also be configured as a digital I/O
port. Information on programming the digital I/O port is found in chapter 5 and under
[SOURce:]DIGital:DATA and [SOURce:]DIGital:FUNCtion commands in chapter 8. The electrical
characteristics of the digital connector are described in appendix A.
Table 3-3. FLT/INH DIGital I/O Connector
PIN FAULT/INHIBIT DIGITAL I/O
1 FLT Output Output 0
2 FLT C ommon Out p ut 1
3 INH Input Input/Output 2
4 INH Common Common
B) Digital Interface Circuits
A) Relay Circuits
INH FLT
. . . .
NOTE: Connectors
are removable
+ - +
Digital Input
Port 2
Relay Driver
Ports 0, 1, 2
(contains internal
clamp diodes for
inductive flyback)
Digital Output
Ports 0, 1, 2
TTL, AS, CMOS, HC
+16.5V Max.
Coil Current
0.25A Max.
4 3 2 1
Figure 3-11. Digital I/O Examples
Computer Connections
The dc source can be controlled through an GPIB interface. Agilent 66111A and 66311B/D units can
also be controlled through an RS-232 interface.

GPIB Interface

Follow the GPIB card manufacturer’s directions for card installation and software driver setup.
Each dc source has its own GPIB bus address, which can be set using the front panel Address key as
described in chapter 5. GPIB address data is stored in non-volatile memory. The dc source is shipped
with its GPIB address set to 5.