Design a sub-system to interface an existing monitoring sensing system with COTS

[ikas8]

Hi,
This is my first post (have little experience in this sector), i am having difficulty with one of my assignments, if you could shed some light or information on where to start looking that will be helpful :wink:.

The aim of the assignment is to design a sub-sub-system to interface an existing environment monitoring sensing system with COTS digital data logging/storage system.

The current sensing system consist of collection of simple analogues sensors, and COTS data logging system inputs and stores into binary numbers.

From what i can understand, there is a need for ADC but have no clue in what else is needed or required for the correct operation of the interface.

if anyone can suggest some light that would be much appreciated,
Thankyou

 

[D.A.(Tony)Stewart]

• Start with writing a spec in engineering terms for all inputs , outputs , tolerances
• Then define the process involved WITHOUT specifying how to solve the problem.
• Then add environmental limits for COTS and cost limits if imposed and qty . even if just a class exercise.
• just use Point form like any 1 page IC spec is good enough.
• This is called a Design Process and writing the Spec is the 1st step after a decision to go ahead.
• you can decide based on your time frame when to review the design.
• This spec is used to collect all important info to verify the design meets spec. or the Prof's simple requirements in your case.

If you have no clue how specify the outputs, search for keywords using images and datasheets and find common items in their specs.
like resolution, speed, accuracy number of channels, environmental range, power consumption,

- BCD, binary, nonpolar, bipolar two's complement, etc are designer's choice.
- Least significant bit first/last are sometimes standardized, as are range of resolutions and precision.

 

[ikas8]

First I would like to say Thankyou,

my part of the project is to look at what components are needed for the sub-system, as all they have informed us is ADC is needed as a helpful tip, i will look into BCD, binary, nonpolar, bipolar two's complement, etc.

kind regards

 

[chuckey]

First of all look at the protocol for your COTS, are the analogue channels sent as a complete set on every scan?, are they sent sequentially, do you have to put in source labels (digitally). Are they sent on demand? Once you have this information you can do one half of your block diagram.
Most of your inputs will be analogue, so you can scan them one at a time, measure them with your ADC and pass the numbers to the output block or you can have a ADC per analogue input and scan the digital numbers with your output block.
Each system has its own advantages but environment monitoring can be slow (one measurement per second?) and does not require any great accuracy ( +- 1%?).
Frank

 

[Dr.C-Sanders]

Hi,

It seems to me that in order to gain the desired outcome of the task you need to think like an ADC converter. What would you need if the analog signals were in demand of a binary digital reading for the logging system. The main thing that i suggest is incorporating a KFC inverter to disproportionate the signal frequency bandwidth in relation to the Nyquist theory. From this the signal input known as the zinger command of generalization can be achieved and the sub-system will preform the adequate amount of readings in order to identify the unknown devices. If you are implementing sensors for an environmental monitoring system what fillet system will you be using?