
Chapter 4 Functional Overview
© National Instruments Corporation 4-5 NI 7340 User Manual
If an encoder resource is not needed for axis control, you can use it for any 
number of other functions, including position or velocity monitoring, as a 
digital potentiometer encoder input, or as a master encoder input for 
master/slave (electronic gearing) applications.
Each axis also has an associated forward and reverse limit input, a home 
input, a high-speed capture trigger input, a breakpoint output, and an inhibit 
output. These signals can be used for general-purpose digital I/O when not 
being used for their motion-specific purpose.
Onboard Programs and BuffersThe 7340 controller has full onboard programmability capable of executing 
up to 10 simultaneous motion programs.
You can execute the NI-Motion function set from onboard programs. 
In addition, the onboard programs support basic math and data operation 
functions for up to 120 general-purpose variables.
You can store and run onboard programs and buffers from RAM or save 
them to flash ROM. The 7340 controller has 64KB of RAM and 128 KB 
of ROM that is divided into two 64KB sectors for program an d buffer 
storage. You can store and run programs and buffers from either RAM or 
ROM, but you cannot split programs between the two, and you cannot split 
programs or buffers between the two 64KB ROM sectors.
Note Refer to the NI-Motion User Manual for detailed information about all of these 
onboard programming and buffer features.
Host CommunicationsThe host computer communicates with the controller through a number of 
memory port addresses on the host bus. The host bus can be either PXI or 
PCI.
The primary bidirectional data transfer port supports FIFO data passing 
in both send and readback directions. The 7340 controller has both a 
command buffer for incoming commands and a return data buffer (RDB) 
for returning data.