Introduction on Data acquisition
Data Acquisition systems consists of electronic interface cards used to be placed inside PC's PCI slot to sample analogue or digital signals, converts them to digital signals, acceptable by PC, then software can be used to process signals to any desired form and display the results, generally graphically and on a spreadsheet with facility to transfer data from one application to another.
Now a days data acquisition cards are placed outside PC, connection via USB-2 port to allow maximum number of units to be connected to one PC and ease of transferring cards from one PC to another especially when PC fail, most advanced USB data acquisition cards take power from USB port which can supply 500 mA.
Data acquisition comes in many different models they varies in number of channels, input voltage, resolution, sampling speed, type of channels analogue, digital single ended and differential input.
Advantages of Data acquisition over traditional equipment are summaries below:-
1- A standard PC can be used.
when you are using traditional equipments for research you will still need to transfer results to a PC for further analysis, so there is no point of using traditional equipment at the first place.
2- PC have a large colour screen, signal with high resolution would be better analyzed, no point of using high resolution traditional equipment when your screen is very small.
3- you can use just one data acquisition card to replace oscilloscope, signal generator, spectrum analyzer, voltmeter, frequency meter, Arbitrary wave generator
4- very easy for conducting experiments, you use a lot less wires to connect less equipment to conduct experiments, connecting signal to one input simply can display frequency digitally also on time and frequency domain on a PC, with traditional equipment you will need to wire signal to the oscilloscope, frequency meter and spectrum analyzer which generate noise
5- much lower cost
you only buy 1 units to get the same functions as four traditional units, you replace old technology with new technology.
6- less space
7- much more reliable
you hardly have any problem with data acquisition, simply most what goes wrong with traditional equipment is the power supply, data acquisition takes power from PC
8- no maintenance required nor spare parts, with traditional equipment when thing goes wrongs on developed countries you wait weeks for parts to arrive from suppliers
9- you can write your own software with supplied source code example to create any system. which could have cost tens of thousands if built on a low volume.
11 you create large system using as many data acquisition cards as you have USB ports available to measure any thing, using appropriate sensors
12 easy to set
you can save setting for each experiment then load it at any time, you can't damage equipment by wrong setting
13 all buttons are virtual not hard buttons which breaks or fails.
14 instant help on screen to conduct experiment or experiment wiring.
Pico technology UK offers a very advanced wide range of data acquisition cards at a very competitive price, all cards are manufactured in the UK
Software supplied is royalty free which means universities do not have to speed money on licenses also can make free copies for there students.
list of Some of Pico technology products
1- TC-08
This is an eight channel thermocouple or mV input, USB PC based data logger, you simply connect up to a maximum of 20 TC-08 on one PC which means you can read and record temperature of up to 160 thermocouples on one PC, it accepts all kind of thermocouples K, J, T extra, the software package supplied is free, which means you can make extra copies and update software free from the internet, you can control the sampling interval for example you can record temperature every few seconds, few minutes, few hours or days, display data on form of a graph or spreadsheet, the data can be transfer to excel for further analyses or processing, the software allows you to calculate unknowns by making relation between inputs, you can ADD subtract multiply, use equation or look up tables.
Example of look up table example
real input values Scaled value (corrected)
0 0
1 1
2 2.1
3 3.2
.
.
.
100 102
Lookup table is used when input is non linear or when you know you have signal losses or error in reading due to pressure, noise, length of the thermocouple.
All channels can be set to read millivolts instead of temperature, this way you can compare the milivolts reading to the temperature reading or you can even measure and scales sensors that have mV output within the range of -70 mV to 70 mV, for example pressure, flow, forces, acceleration, light, gases sensors, you use also lookup table supplied by the sensor manufacturer, for calibration.
El005 Data logger Standalone
TC-08 can record thermocouples temperature reading on a PC in a lab, for out door logging you will need a lab top with it, on applications requiring continues temperature recording 24 hours a day, all the year round with temperature points location 100's meters away, Pico Standalone El005 data logger would be more suitable, standalone means it record temperature even if the PC is shut down or disconnected, PC is used just to program logger and download data at any time.
El005 datalogger can records on its memory up to 250 000 reading, PC is used to set recording intervals between 1 to 240 minutes then it can be shut down and turned ON when need to view or loads stored reading, also modem can be connected to allow logger to send its alarm via SMS to a mobile telephone or send speech massage to a landline or mobile phone.
Example El005 datalogger is used to monitor freezers temperature on Hospitals and food factories, if a freezer door left open or freezer fails, temperature will go up, an alarm message will be sent to mobile phone showing normal temperature, current temperature and freezer causing the alarm. The El005 has an internal rechargeable batteries to keep it working for up to 72 hours when mains fail.
El005 can record temperature, voltage current, Humidity and any industrial sensor which have a standard industrial output (4-20 mA, 0 to 10V or 0 to 2.5V)
which means you can record any thing on one system, it works on modular basis, each module called converter is networked to logger via a 4 wire standard telephone cable, which can be installed for up to 2KM distance, converter can be connected any were on the network, up to 10 converters con be connected to one El005 data logger, maximum of ten El005 can be connected to one PC to create a large data acquisition system.
Converters are simply A/D converters they converts the analogue sensors output to digital signal to be sent out through the network to data logger so you can simply plug the converter any were on the network, plug to it relevant sensor then logger automatically detects it when you program the logger.
Available converters are:-
El001
This Converter is a three channel inputs for ambient temperature sensor (type El015), light sensor or switch status sensor (ON/OFF) you can mix sensors, for example you can use channel 1 for temperature, channel two for light and channel three for door status (open/close). or you can use same sensor type for all three channels so as we can have a maximum of 10 converters on one El005 data logger this means, if we to use all three channels one El001 ambient temperature sensors El015 we can make a system capable of recording 30 sensors within 2K distance.
El026
This converter allows Data logger to monitor one zone (humidity and temperature), if we to use ten El026 converters we could cover ten zones (humidity and temperature) on one El005 logger. 2Km distance
EL040 Three phase current converter with 300A current clamps, this converter measure three phase current, ten converter measure ten three phases within 2KM distance
El041 4-channel thermocouple or mV inputs, accepts all types of thermocouples, ten converters allows 40 thermocouple temperature reading within 2km distance
EL037 This is very interesting 4-channel converter, each can be configured to read 4-20mA, 0 - 2.5V or 0-10V by moving a jumper, reading can be scaled, units can be named, this means you can use all kinds of industrial sensors, flow, pressure, Gases, wind speed and direction, RPM, industrial analyzers.
Application Example:
El005 Datalogger has the following converters and sensors,
one El001 converter ,
two El026 Humidity and temperature converter and sensors,
one El041 thermocouple converter with four K- type thermopile
one El040 three phase current converter with
300A current clamps
three El037 general purpose converter
El001 with El015 ambient temperature on channel one, to monitor air-conditioning temperature, El029 door sensor on channel two to monitor emergency door status(open/closed) and EL031 light sensor to alarm if staff room light left ON.
El026 to monitor the server room humidity and temperature because high temperature can cause a serious damage to server, low humidity cause static discharges which can damage server, high humidity cause Server PCB's to corrode.
El040 to monitor factory phase balance, to worn if a machine warned out requiring a maintenance to prevent breakdown.
El041 with 4 K-type thermocouple to measure oven temperature around 250 degrees.
El037 with 4-20 mA output level sensor on channel one to monitor Diesel and water level, on channel two, flow sensor with tantalizer to monitor Nitrogen gas consumption, on channel three differential pressure sensor to monitor differential pressure at production rooms, on channel four, 4-20 mA industrial analyzer measures product moisture.
ADC-24 is 24 bit integrated I/O USB card, USB connection, 16 channels single ended inputs -2.5 to 2.5 volts, 4 channel configurable digital input output, you can use any pair of channels as a differential input channel which means you can have up to 8 differential input channels, differential input can be used when you need to compare two values, for example difference between air pressure in two rooms at a factory which is called differential pressure, the value will be 0 when both rooms are at an equal pressure, when one is higher than the other the reading will change more positive or negative depending on how you configure them, ADC-24 is programmable to sample between 1.5 to 16 sample per second which means the advantages is that most noise will not be picked up, 24 bit resolution allows sensor with micro volts output to be used, generally you lose accuracy for speed. on Data acquisition, the higher bits number the more accurate your reading but sampling will be slower.
All the above data loggers measures slow changing signals, if the signal is changing faster than 16 time per second, for example flow sensor or speed sensor with pulse output of 200 pulse per second, you will not be able to capture the single directly with ADC-24 you will need to use digital to analogue converter to convert the pulse to analogue value between -2.5 and 2.5 volts, you can use ADC-11 which capture 15000 sample per seconds which means it can capture the signal with frequency of 7.5Khz easily. if the minimum signal is more than 2mv for ADC-11 10 bits.
ADC-11 Data logger Two models of ADC-11, the difference is in resolution, 10 bit or 12 bit, both have 0 to 2.5 volts 11 analogue and two digital output channels they are less accurate than the ADC-24 but faster, so when sensor output is above 2mV and is not changing faster than 7.5Khz it is ideal.
for higher frequency use Picoscope range 5 Mhz to 12Ghz
Pico scopes
Pico technology UK manufacture in the UK one of the best available PC scopes offered at a very competitive price. the oscilloscope connects to PC USB-2 they are Oscilloscope, Signal generator, Arbitrary waveform generator, spectrum analyzer, volt meters at the same time the difference is on the number of channels 1 to 4 and frequency range 5Mhz to 12Ghz. price depends on the Frequency,
please follow the link to see the different available scopes.
All Pico products comes with two Free Software packages one for data logging called Pico log the other is oscilloscope called Pico scope, when you are using Pico log you can monitor, scale, use lookup table, name inputs and records at any desirable interval, every mS, S, Hours or days this is good when you designing you own monitoring station, the software displays the values on a graph and spread sheet format, like the Environment data logger El005 for fast changing signals.
The oscilloscope is good for testing sensor output or noise on sensor wiring, for example you can see the changes in square wave output generated by Flow sensor and discover any noise causing problems.
Pico Supplies Supply Software drivers with examples for VB, VC, Lab view, Delphi, this is for people who would like to write their own process monitoring and control applications the software examples will give you a simple software source code reading sampled channels and displaying the values on a simple form, you can modify the program to make a very powerful software package to suit your application.
Prices for All Middle east countries is exactly the same as one Pico website Pulse 50 Shipping and any customs duties, most middle east countries duties is 0 but sales tax varies,
