Chapter 3
Configuring Your SCXI Hardware and Software
©
National Instruments Corporation
3-33
Jumper W1, when set to position P, connects a 2.2 k
Ω
pullup resistor to the
SERDATOUT line. An open-collector driver drives the SERDATOUT line.
An open-collector driver either actively drives low or goes to a
high-impedance state, relying on a pullup resistor to make the signal line
go high. If too many pullup resistors are attached to the SERDATOUT line,
the drivers cannot drive the line low. To prevent this, set jumper W1 to
position P on only one of the SCXI-1141/1142/1143 modules that are
connected to the DAQ device in a multiple chassis system. It does not
matter which of the SCXI-1141/1142/1143 modules that are cabled to the
DAQ device has the pullup connected.
Tables 3-25 and 3-26 list the description and configuration of the
configurable jumpers.
Table 3-25.
SCXI-1141/1142/1143 Chassis Jumper Configuration
Jumper
Description
Configuration
Pullup—Use this position for a cabled
module in a single-chassis system or the first
chassis in a multichassis system
(factory-default position).
No Pullup—Use this position for cabled
modules in additional chassis in a
multichassis system.
W1
NP
P
W1
NP
P
W1