Research # 1
ACTIVATION OF COUNTER FUNCTION IN NI PCI 6024E FOR READING INCREMENTAL POSITION ENCODER
Abstract
The instrument of incremental rotary encoder is commonly used in the application of speed measurement and distance measurement. The incremental rotary encoder converts the angular position of a shaft to the pulse information on its output channels. In order to decode the pulse information from incremental rotary encoder, counter is used for this process. Counter which is used in this seminar is NI PCI 6024E. The problem for using this DAQ board is no support from National Instrument for using this card in the RTLinux operating system on RedHat 9 distro. Therefore, the solution which is available to solve this problem is COMEDI. COMEDI is open source driver which is legally not supported by NI, so the testing for appropriateness and reliability of COMEDI must be performed.
This article studies about implementation and evaluation of the application of incremental position encoder. The application of incremental position encoder counts input signal from the simulator of incremental rotary encoder. In the final analyses, the application of incremental position encoder gives the accurate results in reading counter so these results can conclude that COMEDI is reliable as the driver for DAQ board NI PCI 6024E.
In this article, the testing for the application of incremental position encoder only performs on the simulator of incremental rotary encoder. Therefore, the next development for the application of incremental position encoder must be testified in the actual incremental rotary encoder in order to determine the appropriateness from this application in reading incremental rotary encoder.
The design of the reading incremental position encoder application:
Research # 2
SPEED MEASUREMENT BASED ON REAL TIME LINUX
ABSTRACT
Real time program has become more powerful than non real time program because of its preemptive and deterministic characteristic. Hence the ability of real time program in deciding the priorities of works and accurately performing the specific work on the precise timing, real time program is suitable for the implementation of measurement applications.
This final assignment studied about the design and implementation of speed measurement based on real time Linux by using M Method as its measuring method. The speed measurement is worked on RTLinux operating system and its measuring device is a 100-resolution incremental rotary encoder and a data acquisition board NI PCI 6024E. This speed measurement will measure the speed of DC motor Pittman Express model GM87 12-21.
The RTLinux speed measurement consists of three programs which are interacting each other. The purpose of the whole three programs is to perform the calculation of speed and put the data of speed and pulse position on graph. Besides, those programs also save the data of speed and pulse position in the time domain to a file.
According to the experimental results, it is concluded that the RTLinux speed measurement is reliable on measuring the speed of motor. The RTLinux speed measurement has the small percentage of error in measurement which is 6.26%. This experiment is performed by comparing the results of the RTLinux speed measurement and the result of tachometer speed measurement. By using least-square regression method, the coefficient of determination is 99.999% for the linear model of relationship between RTLinux speed measurement and tachometer speed measurement. It is proved that the result of RTLinux speed measurement is linear to the result of tachometer speed measurement.
