Microcontroller

V A microcontroller and 74F1C logic with a +/- 10 percent tolerance on the Udd-... 

Both electronic and microcomputer-based controls require information about the state of the controlled system. Sensors convert different physical variables into an electric signal that is conditioned and typically converted to a digital signal to be used in microcontrollers. The trend in the construction techniques of modern sensors is the use of silicon microstrnctures because of the good performance and the low cost of this type of device. In the energy control scope the main quantities to be measured are the temperature, pressure, flow, light intensity, humidity (RH), and the electric quantities of voltage and current. 

Insertion of the ambient temperatures in Eq. 1 results R0 in and a. Since the ambient temperature is calculated from a polynomial funtion (eq. 2) it is necessary to determine the polynomial coefficients by a least square fit regression over the ambient temperature range 0-50°C. Together with S0,. Si, b, and c, these values are written by the calibration computer to the non volatile memory of the microcontroller. As a calibration check two additional blackbody readings are performed at a third ambient temperature (see Fig. 3.48). 

Fig. 5.53 Sensor control and signal evaluation with microcontroller.

A microcontroller board for sensor read-out was developed in collaboration with AppliedSensor (Reutlingen, Germany). This board provides the power supply and the necessary reference voltages and currents to the sensor chip. The sensor chip is mounted on a socket and connected to the microcontroller. The microcontroller provides a set of commands for programming and reading the on-chip registers, controller parameters and sensor values. The microcontroller also manages the data transfer between the f C interface of the microchip and a serial RS-232 interface for external read-out via a PC. The data stream is continuously read out in the measurement mode. Each data set contains the temperature of the microhotplate, the chip... 

The microcontroller board, which is connected to an RS-232 interface of a PC, and a 5.5 V power supply, is all that is needed to control and operate the sensor system. 

The chip is a standalone microsensor system that does not need any external measurement equipment for sensor control and readout. The sensor system chip has been connected to a computer via an f C-to-USB converter box, i.e., in this box is a microcontroller that translates the I C format coming from the chip into USB format for the computer or laptop. The power supply of the chip is also provided by the USB connection. The sensor system can be read out directly by a microcontroller and is, therefore, well suited for handheld devices or distributed sensor networks. 

If the DCCS is required to replace an existing control system (i.e. if the plant is being retrofitted) then the microcontrollers will normally be located in the central control room (CCR). In this case, the distribution features of the DCCS will not be fully utilised and the significance of the digital data highway (DH) will also be reduced. 

Microcontroller based electronics capable of automatically controlling pneumatic pressure to the bladder by sensing and maintaining pressure within 10 mmHg... 

A separate I/O section controlled by a microcontroller including digitizing the trackball and 8 slide potentiometers... 

STANDARD INSTRUMENTS, MICROCONTROLLERS, SMART INSTRUMENTATION VERIFICATION... 

The practices contained in this section apply to all standard instruments, microcontrollers, and smart instrumentation (e g., weigh scales, bar code scanners, controllers, vision systems and EPROM s) considered part of a computer system. This equipment is driven by programmable firmware. 

All computer systems performing regulated operations must be validated. To support computer systems validation, standard instmments, microcontrollers, and smart instrumentation are functionally tested (black box test) and the installed versions recorded. 

The installation of standard instmments, microcontrollers, smart instrumentation, and its associated components is verified according to normal software installation qualification practices. (Refer to Software Installation Qualification in this chapter.)... 

The operational qualification for standard instruments, microcontrollers, and smart instrumentation consists of a black box test. This type of test is based on the user s firm application requirement and challenges a program s external influences. It views the software as a black box concerned with program inputs and its corresponding outputs. The black box testing must consider not only the expected (normal) inputs, but also unexpected inputs. Black box testing is discussed in Chapter 9. 

The following project activities described in Chapter 7 are also applicable to standard instruments, microcontrollers and smart instrumentation ... 

Standard Instruments, Microcontrollers, and Smart Instruments are usually connected to a device to record their data. It is uncommon for them to contain functionality that supports electronic signatures. The majority of these systems are hybrid systems and if this is the case, the Part 11 areas to be assessed include ... 

When purchasing system software, standard instruments, microcontrollers, smart instruments, and standard software packages, it is the practice of organizations to initially rely on the history of the supplier and the industry operating experience as assurance of the supplier capability of program performance suitability. 

Atm 02] Atmel Corporation, AT91 ARM Thumb Microcontrollers, AT91M55800A, 2002, available at http //www.atmel.com... 

Kar 99] Karakehayov, Zdravko, Knud Smed Christensen and Ole Winther, Embedded Systems Design with 8051 Microcontrollers, Dekker, 1999. 

Pump pulsation may significantly impact on mixing quality and in this way the whole reaction performance [108]. In order to minimize this detrimental effect, commercially available syringe pumps were modified in order to suppress temporary pulsations. By this measure, pulsation spikes could be damped after installation of an additional switching valve in combination with a microcontroller for the individual control of both pistons. 

The electronic control circuitry is situated in two levels below the MCB layer with the modules. It is based on a microcontroller system for the micro liquid handling and the chemical analysis data. Implemented in the electrical circuitry are driving circuits for the micro pumps, sensing circuits for the flow sensors, optical absorption measurement circuitry, power management and communications using an RS232 interface. 

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