user manual

Chapter 4 Functional Overview

when implementing dual-loop control, such as in backlash compensation,

which reduces the number of encoders available for other axes.

Note Refer to the NI-Motion User Manual for more information about configuring axes.

Motion Resources

Encoder, DAC, ADC, and motion I/O resources that are not used by an axis

are available for non-axis or non-motion-specific applications. You can

directly control an unmapped DAC as a general-purpose analog output

(±10 V). Similarly, you can use any ADC channel to measure

potentiometers or other analog sensors.

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 position breakpoint output, and

an inhibit output. These signals can be used for general-purpose digital I/O

when they are not being used for their motion-specific purpose.

Note When a resource is mapped to an axis, all features and functions of the resource are

available as part of the axis. Because resources are referenced by axis number after they

are assigned to that axis, it is not necessary to remember or use the resource number

directly when accessing these features.

Onboard Programs and Buffers

You can use the real-time operating system on the NI 7350 motion

controller to run custom programs. This functionality allows you to offload

tasks from the host processor and onto the motion controller. Onboard

programs run at the lowest priority and are therefore reserved for

non-time-critical background tasks. Each program is guaranteed at least

2 ms of time every 63 ms. You can adjust the guaranteed time from 2 ms to

20 ms using the Load Program Time Slice VI or function. Refer to the

Changing a Time Slice section of Chapter 14, Onboard Programs, of the

NI-Motion User Manual for more information and the impact of changing

the onboard program time slice.

You can execute the NI-Motion function set from onboard programs.

In addition, the onboard programs support basic math and data operation