Chapter 3
Configuration and Operation
© National Instruments Corp.
3-5
GPIB-140 User Manual
The two GPIB extenders in the extension system do not need to be set to the same PPR
mode. The PPR mode of the local GPIB extender should be chosen to accommodate the
Controllers on the local GPIB system. Likewise, the PPR mode of the remote GPIB
extender should be chosen to accommodate the Controllers on the remote GPIB system.
If no Controllers are physically connected to one of the GPIB extenders, the PPR mode of
that GPIB extender has no effect on the system.
Setting the PPR Mode
Use switch position 3 on the DIP switch of each GPIB extender to set the PPR mode.
Slide the switch down to the ON position to set immediate PPR mode; slide the switch up
to set latched PPR mode. See Figure 3-3.
OFF
ON
PARALLEL POLL IMMEDIATE
HS488 ENABLE
BUFFERED TRANSFER
= Not used to set Parallel Poll Response (PPR) mode
Figure 3-3. Switch Setting for Immediate Parallel Poll Response (PPR) Mode
Operating the Extension System
The GPIB-140 or GPIB-140/2 extension system is fully operational when power is
supplied to both units and the fiber optic cable has been properly connected.
Three indicator LEDs labeled POWER , LINK , and ERROR, give information about the
operational status of the GPIB extender.
POWER LED
The POWER LED is lit whenever power is supplied to the GPIB extender and the power
switch is in the ON position.