Posts by Farahat

Closed Loop Control The simulation design uses the index output of the servo module for feedback, because this is easier to implement in a prototype. The signal can be generated by making one opto-sensor mark on the shaft (or magnetic equivalent) or one slot or hole in a disk attached to the shaft. One pulse […]
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Motor Control Methods The programs described below have been tested on a previous version of the hardware, and in simulation mode waith the current design. Open Loop Control Open loop control of a dc motor (MOT1) has been described in Chapter 8 and a program developed which allows the speed to be controlled manually. In […]
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Application Enhancements It is always useful to consider how an application design could be improved, even if it is ultimately decided that the design effort or extra hardware costs are not justified by the improved performance. As mentioned above, the PWM module could be used to control the speed of the fan. The display could […]
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Temperature Controller Test Program Program 13.1 was written to exercise the hardware and to get started in developing applications for the TEMCON2 system, using hardware built to this design or the simulation download. The program will read in the analogue inputs (select the test inputs by setting the dual in-line (DIL) switches on) and display […]
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Hardware Development The circuit was developed using Labcenter™ ISIS schematic capture software, a component of Proteus VSM, which provides animated drawing objects for integrated software and hardware testing (see Appendix E for details). When the circuit had been tested by simulation, a stripboard implementation was devised (Figure 13.4). This layout was designed for an earlier […]
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TEMCON2 Temperature Controller The 16F887 has a comprehensive set of peripheral features, including 14 analogue inputs, three timers, four ECCP (Enhanced Capture Compare PWM) channels, extended universal synchronous asynchronous receiver transmitter (EUSART), MSSP (Master Synchronous Serial Port) and in-circuit debugging (ICD). The ’887 is a pin-compatible replacement for the 16F877A, with some extra features such […]
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Motor Application Board MOT2 We will investigate these ideas via a general purpose motor test board design, MOT2, which can control a dc motor requiring up to 30 A drive current. This is provided by a full bridge driver that allows bidirectional speed and position control with pulse feedback (servo motor). MOT2 is based on […]
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Dizi84 Applications Titles for a set of programs to run on this hardware are suggested below. Three applications (*) will be described in some detail, while a further eight will be specified and the source code listed. These form a set of applications suitable for group assignment work in a training program. An ISIS schematic […]
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Dizi84 Board Design A circuit will now be designed, and a set of programs provided, to illustrate the hardware design process and programming principles discussed in previous sections. The DIZI board will allow the user to experiment with the various features of the PIC hardware and programming techniques. Hardware Specification The microcontroller demonstration board will […]
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Logical Errors When all syntax errors have been eliminated the program will assemble successfully, and the hex file will be created. However, this does not necessarily mean that it will function correctly when downloaded to the chip; in fact, it probably won’t! Usually there will be logical errors, particularly when learning the programming method. Mistakes […]
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