©
National Instruments Corporation
2-1
GPIB-120B User Manual
2
Hardware Overview
This chapter describes your GPIB isolator/expander.
GPIB-120B LEDs
The GPIB-120B has seven light-emitting diodes (LEDs). The POWER
LED on the left side of the isolator/expander is lit whenever you power on
the GPIB-120B.
For each bus, an LED indicates the status of the System Controller, Active
Controller, or Source Handshake state, as shown in Figure 2-1. LEDs
associated with Bus A are green, while those associated with Bus B are
amber.
Figure 2-1.
Front View GPIB-120B
Power On (PWR)
When you power on the GPIB-120B, all circuitry is cleared to an initialized
state. The isolation/expansion system is fully operational when you power
on the GPIB-120B and your instruments are connected. Where there is
GPIB activity, it is recommended that you keep at least two-thirds of the
devices on both buses powered on.
I
0
GPIB-120B
Isolator / Expander
PWR
SC
AC
SH
SC
AC
SH
