Tuesday, March 13, 2018

Instrumentation Amp - Op-Amp Designs

This is the best Instrumentation OpAmp, Great CMRR, ensure supply has no ripple and keep analog and digital grounds separate. Ri can be replaced with a trimpot and resistor to alter gain. Connect a preset ends to pins 1 and 8 and preset wiper to VCC for Offset Null when high gains are configured.

Instrumentation Amp - Op-Amp Designs

Instrumentation Amp - Op-Amp Designs

The Input zeners and diodes form a protective clamp for all voltages above VCC-VDD. If supply is changed to +12 -12 change zeners to 12V zeners. Use similar Zeners at output to protect Output from being zapped by over-voltages or high energy - voltage or frequency transients. Add plastic capacitors across Rf for damping AC operation or ripple. Also avoid floating inputs by providing a bias, till you connect it to a sensor; or you will see electrometer like effects.

Monday, March 05, 2018

Analog Interface for PC Ports

Here are examples of an analog Input and Output interface for Printer Port. There are two visual basic demo programs with source to test out idea.

Analog Interface for PC Ports

USB and wireless interface to PC may be more in vogue, but a higher speed is possible in printer-port. For analog and digital fast data acquisition, PC cards to full Access to PC bus are the best choice.

Analog Interface for PC Ports

The Sensors and Actuators interfaced with a computer form a basic automation system or even a robot. So learning to interface Sensors (input devices like a thermocouple or pH sensor) and Actuators (output devices like a motor or heater) with a PC is the best way to start. It is by studying examples and experimenting cautiously can one learn the science, book reading alone will never help.

See the Hardware Book connector details, cables, adapters, etc. The RS232-Serial Port, The Parallel- Centronics port, The USB-firefire port are good to start with. Then you can interface by LAN or Wireless- LAN or TCP/IP-Internet to make Robots or Automation extend to multiple places and computers. The possibilities are endless, imagination is the limit for students. But entrepreneurs need to be practical and only make equipment that have a utility and sensible market scope.

The circuits and code have some errors, The documentation is not complete.
DVM = digital volt meter MVS = milli volt source

Thursday, March 01, 2018

Mixed Electronic Designs

Analog Designs have to handle Linear Signals, Like 2.03 V and 35.3812 mA. Waveforms of all shapes from Straight Line DC Levels to the Jittery and Multi-Frequency Audio Waveforms.

Digital Designs manage Digital Signals, Like 0 and 5V Logic levels. All families of digital Logic, have some Threshold Limits and Voltage windows to determine Data Voltage or Current levels over Noise; this (Analog) comparator like action evaluates a High or Low Logic state. There are only two states, one is Low and the Other is High. 0 and 1 Respectively. The Third State in the word like Tristate, is a floating high impedance for Bus sharing between devices.

Mixed Electronic Designs

I would like to understand Mixed Circuit Designs as any circuit made of Valves, Discretes or Chips; in which both Analog signals and Digital Signals are Used. That would make an Analog Mux a Mixed Circuit, so also a PLL and a VCO.

Mixed Design Example

This is a R-2R Digital to Analog Converter, It converts a byte (8 bit) to a analog value. It has 256 levels including zero. This can be used to convert a byte sent from a microcontroller to a analog value like say 1.51 V. At full scale, when all 8 bits are high calibrate to give 2.55 V then ever bit increment is 0.01V, 10mV steps.

Digital to Analog with R2R Ladder Network

Mixed Circuits Analog with Digital

Mixed Signal IC or ASIC are chips that are mainly Digital on the Core but have peripheral I/O within the chip to interface with the real world outside, over Analog Signals. Sensors and Actuators use signals in the analog language. The CPU with its Math Power, speaks Digital Words, its behavior thus can be patterned by a Software Program.
RF Microwave and Communication Chips; Power Electronic PWM Integrated Circuits are Specialized Niche Mixed Sub-Domains.

Therefore any Student of Robotics, Multimedia and Instrumentation, must be good at these Mixed Designs and a master of C Programming.

Related Resources

Applied Technologies

Applied Technologies
Companies, Concepts, Ideas, Computing. Standards. Quality, Methods, Institutes.

Interesting Posts

Search This Blog