Programming instructions

Chapter 14 SCXI Hardware
DAQ Hardware Overview Guide 14-4 www.ni.com
SCXI-1200 with the input channels from other analog input modules in the
chassis during the same scanning operation.
You cannot use the SCXI-1200 to read channels from other analog input
modules that are configured for parallel mode.
Multiplexed Mode for Analog Output Modules
The SCXI-1124 analog output module supports only multiplexed mode
(sometimes referred to as serial mode in the SCXI-1124 User Manual).
This means that NI-DAQ sets the analog output channel states by
communicating serially over the SCXIbus. Because NI-DAQ can
communicate with the multiplexed modules over the SCXIbus backplane,
you only need to cable one multiplexed module in each chassis directly to
a DAQ device in the computer, or you can use the SCXI-1200 DAQ
module to communicate with all other multiplexed modules in the chassis.
Multiplexed Mode for Digital and Relay Modules
Multiplexed mode is referred to as serial mode in the digital and relay
module hardware manuals. When you operate your digital or relay module
in multiplexed (or serial) mode, NI-DAQ communicates the module
channel states serially over the SCXIbus backplane. The SCXI-1162,
SCXI-1162HV, SCXI-1163, and SCXI-1163R modules have jumpers that
you must set correctly for the module to operate in multiplexed (or serial)
mode. Because NI-DAQ can communicate with the multiplexed modules
over the SCXIbus backplane, you only need to cable one multiplexed
module in each chassis directly to a DAQ device in the computer, or you
can use the SCXI-1200 DAQ module to communicate with all other
multiplexed modules in the chassis.
Parallel Mode for Analog Input Modules
When an analog input module operates in parallel mode, it sends each of its
input channels directly to a separate analog input channel of the DAQ
device cabled to the module. You cannot multiplex parallel outputs of a
module on the SCXIbus; only a DAQ device that you cable directly to a
module in parallel mode has access to its input channels. In this
configuration, the total number of analog input channels is limited to the
number of channels available on the DAQ device. In some cases, however,
you can cable more than one DAQ device to modules in an SCXI chassis.
For example, you can use two Lab-PC+ devices and cable each one to a
separate SCXI-1120 module in the chassis operating in parallel mode. You