ADLINK Technology PCI-8102, User Manual, Page: 53 / 210

Operation Theory 43
4.1.4 Software Real-time Motion Control Kernel
For motion control kernel, there are three ways to accomplish it.
They are DSP-based, ASIC based, and software real-time based.
A motion control system needs an absolutely real-time control
cycle and the calculation on controller must provide a control data
at the same cycle. If not, the motor will not run smoothly. Many
machine makers will use PC’s computing power to do this. They
can use simply a feedback counter card and a voltage output or
pulse output card to make it. This method is very low-end and
takes much software effort. For sure their realtime performance,
they will use a real-time software on the system. It increases the
complexity of the system too. But this method is the most flexible
way for a professional motion control designers. Most of these
methods are on NC machines.
4.1.5 DSP Based Motion Control Kernel
A DSP-based motion controller kernel solves real-time software
problem on computer. DSP is a micro-processer itself and all
motion control calculations can be done on it. There is no real-time
software problem because DSP has its own OS to arrange all the
procedures. There is no interruption from other inputs or context
switching problem like Windows based computer. Although it has
such a perfect performance on real-time requirements, its calcula-
tion speed is not as fast as PC’s CPU at this age. Besides, the
software interfacing between DSP based controller’s vendors and
users are not easy to use. Some controller vendors provide some
kind of assembly languages for users to learn and some controller
vendors provide only a handshake documents for users to use.
Both ways are not easy to use. No doubtly, DSP based controller
provide a better way than software kernel for machine makers to
build they applications.
4.1.6 ASIC Based Motion Control Kernel
An ASIC-base motion control kernel is a fair way between soft-
ware kernel and DSP kernel. It has no real-time problem because
all motion functions are done via ASIC. Users or controller’s ven-
dors just need to set some parameters which ASIC requires and
the motion control will be done easily. This kind of motion control